Talk:Single-lens reflex camera
|WikiProject History of photography||(Rated Start-class)|
|WikiProject Photography||(Rated Start-class)|
- 1 Definition?
- 2 Pentaprism?
- 3 Uncategorized chat
- 4 K1000
- 5 Impotance of SLR camera in this digital era.
- 6 Rangefinder vs. Reflex
- 7 Is the cross-section correct?
- 8 Aperature
- 9 The history: Is it too simple? Is it even correct?
- 10 SLR-like
- 11 Filters
- 12 Guillemets
- 13 SLR chronology
- 14 Awful article
- 15 Split focus thingy
- 16 Mirror Lock-Up
- 17 Wrong photo
- "Prior to the development of SLR, all cameras with viewfinders had two optical light paths..."
This sadly muddled article starts with a thoroughly confused definition and it's downhill all the way. When I have some time, I'll help repair it. After all, there are close to half a billion SLRs in use on the planet, Wikipedia should at least contain a coherent article on SLRs. As for definition, try this, simply: 'A SLR (Single-Lens Reflex) camera is a photographic apparatus which arranges a single lens and mirror for viewing and capturing an image. For viewing, the lens projects the image to a mirror which reflects the image to the viewing and focusing screen. For exposure, the mirror flips out of the light-path, allowing light to reach the sensor or film.' Then we can begin ... Dpwriter (talk) 08:52, 23 August 2010 (UTC)
- In the diagram the light path through the roof pentaprism is shown in simplified form. In fact an odd number of reflections are required to rectify the image on the ground glass screen. The first reflection from the moving mirror requires an additional three reflections inside the prism. Two only are shown.
There's not a single diagram in this page. Does this paragraph make any sense? I have commented it out (using HTML tags). If anyone thinks it is one of the "Advantages" of SLRs (yes, it was listed there), then please clarify the text before placing it back.
- SLR cameras also avoid the difficulty of parallax in close-up photography.
I personally own a SLR (Nikon FM2),have read the Nat'l Geographic Field Guide, and have a tickling in the back of my mind--can almost remember what that would mean, but not quite. So I'm certain that the average person who reads this article will also not know what it means. --KQ 17:08 Sep 5, 2002 (PDT)
In fact, we should include an article on rangefinder cameras, unfortunatlly my english is too poor.
- I can not remember how parallax comes into play on other cameras in closeups - I guess I should dig out my Field Guide and see if I can clarify it myself - but I wanted to be certain that I understood. --KQ
Too make it simple, what you see in the finder is not what you get on the film. The problem has no importance if the subjet is 1.5 m away or more but became more and more critical the closer you get.
In the 50's SLR cameras like the Exakta were tricky to use, and were mainly used for macro while press photographer used mainly rangefinder camera.
- Let me just point out, kindly, that you will see the Exakta being used with a long telephoto lens in the Alfred Hitchcock Movie "Rear Window" so it isn't being used for macro here. Sorry but this statement can't be clarified; it's opinion only.--MurderWatcher1 22:05, 18 September 2007 (UTC)
by the way the rangefinder is also a system based on parallax....
The problem is that, from slightly different positions, objects are in diferent angular positions (close on eye, the the other). In a SLR camera you see what you get, from the same position: no angular difference, in a viewfinder camera, the viewfinder and lense are a bit appart from each other: objects are in different angular positions, for close object, that could mean the difference between being in and out the picture.AstroNomer 17:36 Sep 5, 2002 (PDT)
- Ah. Thanks, both, for the explanations. :-) --KQ
- This ofc applies as much to unwanted objects as wanted objects. For example if you put your finger over the lens on a viewfinder camera you won't notice until the pictures are developed! Plugwash 19:53, 2 March 2006 (UTC)
- To comment on the above sentence, no system is based on parallax! The design of the rangefinder just creates the problem of parallax which no photographer wants at all! Parallax is handled in some high-end rangefinders by using a movable frame in the viewfinder which becomes smaller and moves to the bottom-right hand portion of the rangefinder window, as is the case of certain Leica rangefinder cameras. As you focus closer to the subject, the frame moves closer to the position of the lens in order to eliminate parallax, but it's only giving you an approximate means to frame your subject; not an exact way, as is the case with SLR's.
- There is NO PARALLAX at all in Single Lens Reflex cameras simply because the viewing optic(s) are related to the camera lens. You're viewing a live image through the lens used for the actual exposure on the film. All this, complements to the 45 degree angle mirror, the focusing screen system, the pentaprism, and the eyepiece.--MurderWatcher1 14:30, 7 September 2007 (UTC)
Mirror System Illustration
NOTE: The image showing the principle of the SLR is wrong, I'm afraid:
- To get the image correct wrt mirroring, the light path in the pentaprim is like a "4".
- The mirror is significantly shorter.
- The focussing screen is not shown.
- The three light beams appears not to be influenced by the lenses(!)
Egil 12:16 Jan 28, 2003 (UTC)
I've now made a new drawing which is more correct.
Egil 19:08 Apr 26, 2003 (UTC)
Anon: I think the image still needs improvement. The light is shown as a broad area which collapses to a single ray by the time it gets to the film or eye, which isn't quite true (IIRC). Also, by having the light look like a single ray bouncing around in the pentaprism, you don't show why a pentaprism is necessary. The lens inverts the image, no? (Also not shown.) I'd suggest either using 1 or 2 single rays the whole way through (perhaps one on-axis and one off-axis, of different colors), or using a broad swatch of light all the way through, being flipped by the lens.
Other SLR talk
The Minolta SRT 101 is the first SLR with TTL measure at full aperture, thus it established the standard layout for semi-automatic TTL cameras. Ericd 10:29, 11 Aug 2004 (UTC)
Re SRT-101, that is a pretty well qualified achievement. There are hundreds of cameras with similarly deeply qualified achievements. I don't think it is on the same level with e.g. First SLR system (Nikon F), First "modern" SLR (Pentax), First autofocus SLR (Maxxum 7000). Icd 06:00, Aug 12, 2004 (UTC)
If you had ever used a SLR with stop-down metering you should know that it's a major improvement on SLR. It's at the same level as Pentax achievements : TTL metering and automatic mirror return. Ericd 09:19, 12 Aug 2004 (UTC)
I believe the Canon AE-1, manufactured in 1978, is regarded as a relatively groundbreaking SLR, would that be worth adding to the selection? My source for the information is http://www.mir.com.my/rb/photography/companies/canon/fdresources/SLRs/ae1/index.htm which I believe to be a reliable one, as it covers a wide range of cameras by different manufacturers. The reason for inclusion that I got from the page was essentially "The Canon AE-1 was the first 35mm SLR camera to be controlled solely via a built-in Central Processing Unit (CPU) and made SLR photography avaialble to beginners and amateurs at a reasonable prices". Worth mentioning? 18.104.22.168 08:24, 11 November 2005 (UTC)
Oh forgot to log in.. the above was me. He who says zonk 08:26, 11 November 2005 (UTC)
- While I owned a Canon AE-1 camera and it was a fine 35mm SLR camera, in only one sense was it 'ground-breaking'. The introduction of dedicated flash capabilities. It was one of the first cameras to introduce an inexpensive motor drive called a 'winder', which transported the film at 2 frames-per-second. The Canon AE-1 camera also was one of the first to replace the top and bottom brass plates with inexpensive polycarbonate materials, which were claimed to handle wear better than the chrome-plated brass plates were. The Minolta XG was another camera of roughly 'the same mold', using polycarbonate and an inexpensive winder.
- Before the Canon AE-1, Canon manufactured the EF, also a shutter-priority SLR camera, and this camera's build-quality was higher than the AE-1; however, it lacked the winder ability which the AE-1 had, thus photographers wanting an inexpensive motor drive would select this camera over the EF. Later came the Canon A-1, which WAS groundbreaking! Shutter-priority, aperture-priority, fully-programmed exposure; an incredible LED readout in the finder screen and - in addition to accepting the Canon Power Winder, the camera also had its own dedicated motor drive which gave the camera a top image recording speed of 5 frames-per-second (FPS). Both the AE-1 and the A-1 had an intersting dedicated flash system whereby the dedicated flash was inserted into the camera's hot shoe and the metering system would select the correct synch shutter speed (1/60 second) and then the correct aperture.
- Unfortunately, unlike the Olympus OM-2, the flash unit's own sensor was used to calculate exposure, which made multiple-flash usage and certain types of automatic bounce flash photography impractical because the sensor would be pointed AWAY from the subject when the flash unit was off-camera and aimed, say, at the ceiling. Of course, if the bounce feature of the flash is being used (assuming it has a tilting flash head), then limited bounce flash could be attempted.
- The Olympus OM system used a superior method of metering for the flash off of the film plane, unlike the Canon system, and Olympus made dedicated synchronization cords which greatly increased this camera's flash capabilities, especially for photomacrography (macro photography). Canon's last camera in the FD-lens system line, the T90, was finally manufactured with that capability. The camera appeared strange and unattractive and Canon later made the manufacturing and design decision to change their lens mount from a breech-mount system (later adapted to a kind of bayonet) to a true bayonet-mount system with the EOS camera line. This manufacturing move alienated a lot of Canon owners (myself included; I switched to the Nikon system but that was an expensive switch of 3 or 4 camera bodies and 4 or 5 Canon-mount lenses for Nikon bodies and lenses) and some photographers may have traded their older Canon FD-based lens system for the EOS, or otherwise went with another manufacturer such as Nikon or Pentax. Pentax had their LX, which was the equal of the Nikon F3 with off-the-film, flash-plane metering capability in addition to aperture priority and interchangeable prisms and screens. Both the Nikon and Pentax systems were excellent for macro photography as the photographer had considerable lighting control with those manufacturers' dedicated flash systems.--MurderWatcher1 14:53, 7 September 2007 (UTC)
- Update to the above comments by me; the Minolta SRT-101, while a good camera and indeed having the ability to meter through-the-lens at full aperture, wasn't really the first; it was Topcon with the Super-D (Bessler in the U.S.A.) which was the first production SLR camera to have that honor. As I had mentioned in another discussion, Pentax was the first to make a prototype SLR with behind-the-lens metering, the Spotmatic, which in prototype form and production form, required the photographer to manually stop down the lens diaphragm, meter by centering the meter needle using the lens diaphragm or the shutter speed dial. The Minolta used, what Minolta referred to as "CLC" which was an acronym for "contrast light compensation". In certain situations, however, I understand that it wouldn't work properly because the camera had to be used for standard horizontal photography. When you photographed with the camera tilted for a vertical shot, the CLC might give an incorrect meter reading. Also, Nikon introduced the Photomic 'T' finder for the F-reflex around the same time as the Minolta SRT-101, which gave that camera full aperture metering but in what some might describe as a clumsy method. You had to put the lens on the camera and turn the aperture ring (I think, don't exactly remember; to full aperture then minimum aperture) to index the lens (later Nikon lenses were modified on the rear of the lens mount to get rid of this annoyance and this was evidenced years later in the fully-programmed Nikon FA). Understand also, that the Topcon had its CdS (Cadmium Sulfide Cells) light meter engraved under the mirror glass itself, unlike the Minolta, Nikon or Pentax, which had their CdS meters housed in the pentaprism assembly. Canon did something interesting with their Canon Pellix Camera. They put the CdS meter behind the mirror and it metered directly in front of the mirror. The cell was raised (I believe) by activating the meter first, then lowered during the exposure. Also, the mirror didn't move as it was a pellicle design of Canon's own doing so the camera (supposedly) had less vibration than other SLR's. Unfortunately, in one test report that I had read, the pellicle introduced its own problems by degrading the resolution of the lens, allowing 70% of the light to the film plane and 30% of the light to the photographer's eye. Canon did continue with the idea of a Pellicle Mirror in at least one of their EOS cameras (the EOS 630 I believe and maybe a modified Canon EOS 1) and some older FD-mount F-1 Cameras because it allowed faster motor drive speeds in these specially made cameras.--MurderWatcher1 22:26, 18 September 2007 (UTC)
Difficulty in constructing wide-angle lenses because of the space-consuming mirror movement.
My question is: Wouldn't a telephoto lens require more space due to its greater focal length, than a wide-angle lens (whose focal length would be smaller)? Isn't the article's comment reversed on this? (Or am i missing something here?)
This is right. The problem is that at infinite focus the center of the lens should be at a distance of the film plane that is equal to the focal length. This mean that a 100 mm telephoto will have its center at 100 mm from the film while a 28 mm wide angle will at 28 mm only this doesn't leave enougth space for a moving mirror that should be around 24x36mm for a 35mm camera. For illustration have look at http://cameras.alfredklomp.com/jupiter12/ the Jupiter-12 is a very basic WA design for non-SLR camera and look how deep the rear element goes into the camera. In the fifties they were no WA for 35mm SLR while 35mm were alvailable for Leica. The solution is to use a retrofocus lens. This design allow the lens to have a distance from the film that is longer that its focal length, it's like two lens packed the first one forms the WA image and the second focuses the first image on the film. Obviously this is complex design thus expansive and prone to more aberrations. Retrofocus designs are sometimes called "inverted telephoto", because you can roughly reverse the design to build short (I mean physical size) telephoto lenses. For instance you may find a bit bulky a 300mm lens that will at least 300mm long with a basic design. A telephoto design will allow to build a lens shorter than 300mm. Ericd 00:53, 25 Jun 2005 (UTC)
The K1000 is a notable camera, IMO, because (a) it started the K mount and (b) it was very successful in terms of sales. Yes, it didn't introduce any real technical advances, but that's not in my opinion the only measure of notability. Comments? Matthew Brown 09:36, 17 November 2005 (UTC)
What makes Pentax 'notable' is that the manufacturer had the courage to design a new lens mount, thus discarding their use of screw mount lenses, and to continue using that same mount through today. Pentax, along with Nikon, are the only manufacturers to make a camera system that can utilize a completely mechanical SLR camera body, a fully-automatic autofocusing SLR camera body, and a D-SLR camera body - all using the same mount lenses. The only differences in the lenses themselves would be the internal electronic contacts in the lens mount for exposure data, and the autofocus cams.--MurderWatcher1 19:50, 5 September 2007 (UTC)
No, the K1000 was not the first K-mount camera. The Pentax KX was the first, followed by the K2 and KM. The K1000 was a budget version that just so happened to be made for several decades. — Preceding unsigned comment added by 22.214.171.124 (talk) 03:45, 7 June 2011 (UTC)
Impotance of SLR camera in this digital era.
As i know the advantage of SLR camera is for able to see the exact sean through eye piece (avoids parlox error). Now all digital cameras shows the exact picture on the screen. Then still what is the importance of the SLR camera's. Please some one clarify.
- A digicam screen eats batteries and is very hard to use in bright sunlight. Also the resoloution of the small LCD display isn't sufficiant to use for anything more than selecting the frame area (can't really be used to manually focus or to check the autofocus has got it right). I have a screen only digicam and its pretty horrible to use compared to a camera with a traditional viewfinder. Plugwash 00:29, 26 February 2006 (UTC)
- In addition to the above comment, I would like to say that an SLR viewfinder is usually brighter, clearer and the image more defined than is the case for an LCD screen. There is no eye-strain, as would be the case with continued viewing of an LCD screen. I will say that one of my digital cameras, the Canon PowerShot G7, has a fine LCD screen and when I don't want to carry a D-SLR, this camera is surprisingly good. I wish, however, that the camera had a real wide-angle capability as the lens is the 35mm camera equivalent to a roughly 36 to 210mm camera lens. I would prefer, say, a 24 to 85 35mm camera equivalent, or even wider.--MurderWatcher1 19:55, 5 September 2007 (UTC)
Rangefinder vs. Reflex
I don't know how to include this but when a rangefinder gets autofocus it lost its rangefinder and become a basic viewfinder camera... See Konica Hexar AF or Contax G. Ericd 15:54, 6 December 2005 (UTC)
- These cameras should be considered as rangefinder cameras only and not included on this page. Sorry for the long-awaited response!--MurderWatcher1 (talk) 23:12, 7 December 2007 (UTC)
Is the cross-section correct?
I contribute mainly to the french wikipedia and worked recently on the french version of this article. It uses the same cross-section picture (as do many other international Wikipedia's). Recently, someone stated that this picture is wrong, that it shows a wrong number of reflections in the prism. Personnaly, I seriously doubt it and would rather think that the US, DE (etc...) articles are correct. Only this user reverts every time I remove his comment. So I guess I need some extra sources to convince him (or maybe he's right after all, who knows?). I made some search but found nothing except copies of this US wikipedia article on other websites...
Does someone may an extra source/reference then?
The only (small) critic I have against this picture is that it doesn't show inverted rays after the lens, but it's not treally the point of this article to explain the way lenses work. As a side note, I got the same problem (with the same user) with the picture illustrating a roof pentaprism, so I asked a similar question in the "Talk" page of this article. --Jérémie A. 13:12, 28 February 2006 (UTC)
The diagram does not show the aperature. It would be nice if it was included.
Erland Lewin 14:33, 28 February 2006 (UTC)
- The aperture is irrelevant to the concept being shown, and adding an iris diaphragm would be an unnecessary complication. -- Hoary 11:16, 2 March 2006 (UTC)
The history: Is it too simple? Is it even correct?
This page reminds me of some innovative SLR cameras I'd known of (including the Rectaflex, Miranda, and Zunow), as well as some I didn't: notably the Gamma Duflex of 1947, "with instant return mirror".
Some things claimed in this Wikipedia article to be firsts don't seem to be firsts. I hesitate to edit, because I suspect that a number of the firsts that predate the "firsts" in the article might need qualification with "however" (and not only "however, it was not commercially successful" but also "however, it was unreliable and easily broke down" or "however, it only functioned when combined with XYZ / when the photographer remembered to ABC").
An example is this paragraph:
Through-the-lens (TTL) light metering came to the SLR in the early 1960s, with 1962's Topcon RE Super (spot metering) and 1964's Pentax Spotmatic (center-weighted average metering). Auto-exposure was next, introduced by Pentax in 1971's Electro Spotmatic and popularised with 1976's Canon AE-1 Program, one of the best-selling cameras of all time. Full program auto-exposure soon followed. The 1970s and 1980s saw steadily increasing use of electronics, automation and miniaturization, including integrated motor driven film advance with the Konica FS-1 in 1979, and motor rewind functions.
I don't know the real answer, but I do know the Konica AutoReflex of 1965 was a shutter priority autoexposure camera, and the AutoReflex T of 1967 was a TTL aperature priority autoexposure camera, thus falsifying the statement that "Auto-exposure was next, introduced by Pentax in 1971's Electro Spotmatic." --Kperegoy 02:34, 12 March 2007 (UTC)
There is certainly room for discussing the first critically/commercially successful examples of this or that (whether this success was a matter of particularly good design, marketing clout, low price, or some combination thereof). However, commercial success isn't all: though the Zunow clearly wasn't a commercial success (and for all I know may have been what bankrupted the company), it did seem to have an impact. -- Hoary 11:16, 2 March 2006 (UTC)
- I have serious doubts about parts of the history. This is partly because I have found it very difficult to get histories of photographic equipment that are not single-brand histories. Single-brand histories tend to trumpet the achievements of that brand, and quite often make inaccurate statements, or at least statements that (as you said) need to be qualified. Quite often, when you look into 'first', it turns out to be 'first commercially successful' or 'first widely used', or 'first that really worked well'.
- Thus, if anyone has any idea of general photographic history works that will help - feel free! Matthew Brown (Morven) (T:C) 06:17, 29 August 2006 (UTC)
- Annoyingly, on looking through this article, the history that WAS here has been severely mangled and chopped to bits since I last worked on this article. Editors: if you have problems with the sourcing or NPOV of text, you should question it on the talk page, or if you find it really bad, move it to the talk page at least. The page now misses many critical parts of SLR history, including glossing over the MAJOR impact of the Nikon F - the camera that took professional photography by storm and pretty much wiped out the rangefinder camera as the mainstream 35mm type - and the contributions to the autofocus SLR by Minolta and Canon are now completely gone. Canon's utter dominance from the late '80s on of the professional sports and event photography market is also completely gone. Matthew Brown (Morven) (T:C) 06:55, 29 August 2006 (UTC)
- I 'weighed-in' on this section, based on 40 years of reading photography magazines and the like. I may have to re-read some of these old magazines, which I still have, in order to present a clearer picture of the history of the SLR.--MurderWatcher1 15:09, 7 September 2007 (UTC)
The article (as of 18-Aug-2009) says: "Autoexposure, technically known as semi-automatic exposure, where the camera's metering system chooses either the shutter speed or the aperture, was finally introduced by the Savoyflex and popularized by Konishiroku in the 1965 Konica Auto-Reflex." Yet, the Topcon Auto 100, which is mentioned elsewhere in the article, had semi-automatic exposure also, and it came out in 1964. Perhaps the Auto-Reflex is still a first, but with the qualification of "first shutter-priority semi-automatic exposure?" Since it had TTL metering, the Auto 100 was also the first semi-automatic TTL SLR. Rochkind (talk) 19:51, 18 August 2009 (UTC)
What's the difference between SLRs and SLR-like cameras? All that I can tell is that SLRs don't come with a lens (?), and SLR-likes do. 126.96.36.199 02:01, 20 June 2006 (UTC)
I have just removed this very recent addition: Filters that attach to the end of the lens only increase the options for the photographer. The most commonly used is a UV filter, which is extremely useful for reducing the harshness of sunlight in a picture.
- The first half is true, and also true of various alternatives to the SLR. (Indeed, it could be argued that a red filter is a major pain with an SLR but a breeze with a rangefinder camera.) The second half is simply untrue. -- Hoary 13:22, 12 October 2006 (UTC)
- The correct wording of the first paragraph should be: "Filters that screw into (typical 35mm SLR's) or bayonet onto (Hasselblad lenses) to the front of the lens". You can, in some lenses, insert filters into the rear of the optic, such as certain mirror lenses such as the 500mm f/8 reflex Nikkor Super Telephoto lens; or some fisheye lenses. There are also some interchangeable lenses with built-in filters.--MurderWatcher1 15:16, 7 September 2007 (UTC)
Respectively questioning the usage of the double arrows around the word <<intelligent>> in the first sentence of the “Autofocus” section. Is there a meaning to this or just an oversight? Just a Wiki-rookie trying to help! Bigwig77 01:52, 2 January 2007 (UTC)
- Thanks for catching that. I've replaced the guillemets with double quotation marks. A non-native English speaker probably added them by mistake. --Imroy 05:02, 2 January 2007 (UTC)
- I just saw this. However, we do have some history already in this Wikipedia reference so, anyone else want to 'weigh-in' on this topic?--MurderWatcher1 20:19, 7 September 2007 (UTC)
As with most of wikipedia's articles on technical matters, gets too complex too quickly without first offering an overview of the relative merits of this technology. The opening paragraph is an exercise in convoluted writing. I have given up reading tech articles on wikipedia, as most have or will do so. This is a general issue that has to be resolved, if tech people are left free to edit and make overcomplex something that need not be, adding detail after useless detail the encyclopaedia is not going to benefit for sure. 188.8.131.52 20:51, 6 October 2007 (UTC)
- Agreed, after reading the first "summary" paragraph before the article begins, I had no idea what an SLR was. Maybe something like "an SLR basically allows you to see what the camera lens sees" instead of "The single-lens reflex (SLR) camera is a photographic imaging instrument that currently uses an automatic moving mirror system and viewing pentaprism, which is situated between the lens and the film plane.........." which isn't really helpful unless you already know what an SLR is. jay 05:38, 21 October 2007 (UTC)
- I know what you're both talking about. Personally, I pride myself on being able to write clear text that can explain complicated things in a way so ordinary people can understand it. (I've been told that quite often in my life.) Here at Wikipedia I've tried to re-write a couple of technical articles (not this one) that were way too complicated. What happens? Slowly but surely the text gets revised by editors who add more and more complicated details to the article in general, and even to the introductory section. I don't know if there is any solution to this problem. --RenniePet 14:37, 21 October 2007 (UTC)
- It's really hard to say this is a good article because some of the grammar, etc. is faulty; I've noticed the word "however" too many times and have tried other synonyms to replace this word. A grammar edit or two, etc. but for myself, if I really need to improve this page, I think I'd have to put an "under construction" tag on it and just work on it non-stop for a day or two. That's not very attractive for most Wikipedia editors. We DO have our private lives! I've come back to this page after a two-month hiatus to check the history and find vandalism, etc. Wish some people would take these pages seriously.--MurderWatcher1 (talk) 23:17, 7 December 2007 (UTC)
- I've now jumped in and rewritten the intro to give a better understanding of what SLR is, how it compares with non-SLR cameras, and the recent competition from digital cameras with LCD preview.
- Also, this paragraph further on is mystifying... there seem so many exceptions that the word "anytime" seems nullified to the point of being ridiculous. I'm no expert in this camera product line, but this either needs some serious rewriting or the whole paragraph should be removed:
- Thus, anytime a photographer purchased a lens for the Hasselblad, with the exception of the older Hasselblad 1000f and other focal-plane shutter Hasselblads; or the Zenza-Bronica ETR, ETR-S, ETR-Si, the SQ, the SQ-Ai, the SQ-B, and the G series (with the exception of older Bronica cameras such as the Bronica Deluxe, the Bronica S, the Bronica S2), or the bigger system Mamiya RB-67, RB-67 Pro, RB-67 Pro S (mechanical) and RZ (electronically controlled shutter) cameras, that lens included a leaf shutter in its lens mount.
- I would like to suggest that this article be re-focused to only discuss film SLRs. (I tried to do this once myself, but got promptly reverted.)
- There is an existing DSLR article (although it also has problems), so there is no need for this article to cover both film and digital SLRs, and trying to cover both makes it even more confusing and difficult to maintain. In trying to cover both film and digital SLRs, this article becomes more and more schizophrenic, as it tries to describe what film SLRs are/were like and how they're different from all other cameras, and at the same time tries to describe what digital SLRs are like, as they continue to evolve and become more and more different from film SLRs, while also being different from non-SLR digital cameras.
- Film SLRs were/are a fantastic invention, and deserve an article for themselves. But film SLRs are also a closed chapter, while DSLRs are a different breed and on their way to new things. How can one Wikipedia article do justice to both? It's not possible. --RenniePet (talk) 14:50, 26 December 2007 (UTC) --RenniePet (talk) 15:40, 26 December 2007 (UTC)
- DSLR has a very fuzzy definition, mainly due to the fact that old film SLRs can become DSLRs with the addition of a digital camera back to replace the film cartridge and back door. The "D" in a DSLR can be reduced to a replacement back door with all the digital controls, battery pack, a memory card slot, and a rear LCD preview screen, with the rest of the SLR being film-based. How would you suggest accomodating this if there are two separate articles? DMahalko (talk) 21:23, 26 December 2007 (UTC)
- Ah, well, it was just a suggestion. I hadn't thought of that complication.
- There is also an existing article Digital camera back, so one possible strategy could be to say that this article is only about film SLRs, the DSLR article is only about digital SLRs, and both articles have links to the digital camera back article where information unique to that is covered. --RenniePet (talk) 21:43, 26 December 2007 (UTC)
Split focus thingy
In many SLRs there's a circle at the center of the viewfinder that splits the image, shifting some to the left and some to the right unless the image is in focus. What is the name and mechanism this gadget? —Ben FrantzDale 01:04, 2 November 2007 (UTC)
- It's called a split-image focusing screen. Most recent SLR's (digital and film) have a plain screen without the split-image focusing aid. I guess manufacturers think it's unnecessary now with autofocus being so common. Replacement screens can be purchased though, e.g  (I'm not affiliated with Adorama in any way, I simply found it with a Google search) --Imroy 02:42, 2 November 2007 (UTC)
- The 'canonical' manual focus focusing screen involved a focusing matte covering the entire viewing area, with a central split-image prism surrounded by a microprism collar. All three were useful for focussing in different ways. The modern autofocus SLR has a very fine matte screen and no other focusing aids. The coarser the matte, in general, the more obvious the 'snap' into focus is, but a coarse matte reduces light transmission. Since an AF SLR generally loses a portion of light to autofocus and metering, because cheaper SLRs have less efficient pentamirrors rather than pentaprisms, because most SLRs come with a slow kit zoom rather than a fast prime these days, and because reduced format digital SLRs have less light to play with anyway, it's less desirable to have a screen that doesn't pass the maximum amount of light. Matthew Brown (Morven) (T:C) 07:56, 2 November 2007 (UTC)
- Thanks. I added a request for more technical detail to Focusing screen. —Ben FrantzDale 03:52, 3 November 2007 (UTC)
- I believe Herbert Keppler and some others referred to this focusing collar in the center of the screen as a split-image rangefinder. As —Ben FrantzDale has said, there are many types of focusing screens and you have to find the particular one that is useful to you. When I purchased my first Nikon F SLR, I wanted the type 'F' focusing screen, which had a microprism collar. I really wanted the 'E' at the time but that lacked the microprism and was just a straight fresnel screen, with grid lines, so that you could use this for architectural and landscape photography. Maybe do a search on these if you want more information.--MurderWatcher1 (talk) 23:22, 7 December 2007 (UTC)
"To avoid the noise and vibration, many professional cameras offer a mirror lock-up feature, however, this feature totally disables the SLR's automatic focusing ability."
I think this is misleading. Canon dSLRs do the following when set to use mirror lock-up:
1) Focus when the shutter is half-depressed 2) Flip up the mirror when the shutter is fully pressed 3) Open the shutter 4) Close the shutter 5) Lower the mirror
The autofocus works the same as when not using mirror lock-up.
- What you described sounds like normal non-mirror-lock-up mode; don't you need a second button press at least? The point is that once the mirror is up, you don't get to autofocus again before the second press. Perhaps you can clarify that. Dicklyon (talk) 06:37, 15 November 2009 (UTC)
In the History section, the description of the Olympus OM2 is correct - "Olympus The 35 mm film-based Olympus OM-2, which was the first SLR to measure light for electronic flash at the shutter curtain". But the photo is of the later OM-2SP/OM-2 Spot-Program model, which was not the first. A photo of the original OM2 is needed (I have an OM-2N, which I could photograph, and that would be better - but we really need the original OM2 to accurately show the first model with that feature) -- Boing! said Zebedee 10:03, 5 April 2010 (UTC)