Nontrivial questions about the Mamiya M645 1000s

Discussion in 'Medium Format' started by teodor_oprean, Dec 5, 2009.

  1. Could you please share your insight on these questions I am having? I have tried to find answers to them by searching previous threads on this site and on other photography discussion forums, but I still have not reached the answers I seek. All of them are about the M645 1000s.
    1) Does the use of extremely long exposures via cable release in the bulb setting drain the battery? I am thinking of exposures in the realm of 20 minutes and even an hour. I have done that sort of thing with my other cameras, all of which are entirely mechanical, and I would like to know if the B setting on the M645 1000s is battery-independent. The user manual offers two methods of doing long exposures, one of which involves removing the battery from the chamber(!). That makes me wonder why on earth the manufacturer would recommend such a peculiar way of going about it. Maybe it is implied that the battery might be drained by the conventional method, but it's not clear from the manual because the wording does not explicitly warn against keeping the shutter open on B for long durations of time, so I cannot settle this question on my own.
    2) Is it a sign of impending mechanical failure if the film advance crank/knob randomly switches between requiring a single 360 degree rotation and two 360 degree rotations to advance a single frame? On the second-hand body that I tried, the film advance switches between these two modes intermittently with no discernible pattern. That leads me to worry that there might be something wrong with the gears inside the camera because the user manual shows only one 360 degree rotation for advancing one frame. Is this deviation from the ideal something I can safely ignore? Have other users of the M645 1000s on this forum observed the same behavior?
    3) Is it still possible to buy the original Mamiya focusing screens # 2 (plain) and # 3 (grid) as "new old stock" from a reputable supplier? Did Mamiya originally sell focusing screens in a matching hard case in the way that the 120 and 220 film inserts are usually kept? Ebay at this time offers either used (i.e. scratched and dim) samples of the screens I'm looking for or seemingly brand new samples of these screens: # 1 (microprism center) and # 5 (angled split image center with microprism doughnut). I've tried the # 5 screen, and indeed it is a good screen for general use, but I would like to use the # 2 screen for extreme macro and the # 3 screen for landscape and architecture.
    4) What is the length in millimeters of an "Auto Macro Spacer"? This extension tube is officially intended to be mated with the 80 mm f/4 Macro lens for use between 1:2 (half life size) and 1:1 (full life size), but the ebay prices for this little accessory are too inflated in my opinion, and KEH does not have this item currently in stock. I have the 3-piece macro tube set already, so I am wondering whether the length of the Macro Spacer is the same as the "Auto Extension Ring No. 3-S". (What does the "S" in the name signify?) I measure the length of that individual tube to be 33 mm. Also, the length of all three tubes linked together measures 70.5 mm. (As a completely irrelevant aside, the distance from the film plane indicator to the front of the lens mount of the camera body measures 65 mm.)
    5) Does the "switch ring" of the 80 mm f/4 macro lens alter the inner air spacing between the two halves of the lens for better optical performance in the region 1:2 (half life size) to 1:1 (full life size)? It seems that way from using the switch ring while looking into the lens with the aperture stopped down to f/16. The extra air spacing seems to be exactly 1 mm, and the entire front half of the lens assembly (everything in front of the aperture) seems to be moved forward by that amount when switching the ring to the "spacer" mode. Does this fact complicate life when trying to use the lens for magnifications beyond full life size (e.g., twice life size)? Should one use a reversing ring in that case for best results?
    This is completely different from how the 100 mm f/4 Macro Takumar works in the 35 mm format. With that lens I measure the displacement from infinity focus to 1:2 (half life size) magnification to be exactly 50 mm, which makes perfect sense because 50 mm is half of 100 mm. With the 80 mm macro lens for the M645, the displacement from infinity focus to half life size magnification is only 21.5 mm, which I find surprising. I can certainly appreciate that a shorter displacement makes macro photography more manageable in 645, but I think one would be confused initially by some of the counter-intuitive consequences of that optical compression when one tries to use the lens outside of its intended design. It also leads me to wonder if this idea has been replicated by any other manufacturers of macro lenses for 6x6, 6x7 or large format.
    6) Is lens separation a common fault in Mamiya-Sekor C lenses for the 645 format? I have seen three lenses that exhibit that defect. What I have seen is of a consistent pattern. Usually the separation is close to the perimeter of the optics just behind the first lens element. The separation looks like an elliptical crescent. I've compared that with sample images posted on the website of S K Grimes of other lenses that have the same defect. It looks exactly the same. It is lens separation for sure. Does it degrade image quality appreciably? One lens that has it to a worrying degree is a 300 mm f/5.6 which was classified as "LN-" by KEH. I am contemplating returning the lens, but I am still undecided about it.
    7) The engraving on the right hand scale of the bellows lens hood makes no sense to me. The sequence is messed up. From right to left it reads:
    300 (middle), 150 (middle), 110 (above), 210 (below), 80 2.8 (above), 70 (below), 80 1.9 (above), 55 (below).
    The reason I am confused by that engraved sequence is that the additional mask you have to insert clearly states that it's intended for the 150, 210 and 300 mm lenses. So shouldn't the engraving sequence look like this instead?
    300 (middle), 210 (middle), 150 (middle), 110 (above) etc.
    And why is there a left hand scale with these markers? From right to left it reads:
    2.4 X 3.6 (middle), 4.5 X 6 (above), 6 X 6 (below), 6 X 7 (middle).
    Why would anyone try to use this bellows hood on any other camera even if it were possible with a step-up filter adapter? The aspect ratio of 645 does not match the aspect ratio of 35 mm or of 6x6. And with the Mamiya RB/RZ67 I would expect that an entirely different bellows hood would be offered since the focal lengths used on that camera differ markedly.
    Nowhere in the user manual is there any explanation to clarify the intent behind these two scales of the bellows hood. What information am I missing here? Did the bellows hood originally come with a sheet of paper that explains all of this?
    Thank you in advance for your replies.
  2. I had a very early 645, bought in 1974, in less than 3 years I had to have the film transport gears replaced. The shutter is electronic.....yes they will eat batterys. These are some of the reasons that in 1981 I switched to Hasselblad. Yes it cost more but have not had any problems with my equipment, except light seals in film backs (normal wear).
  3. I'll discuss what I know or think ...
    1. So long as you are in "B" and using a cable release or a finger on the shutter, there is NO battery draw. I hooked a milli-ammeter in series with the battery and some alligator leads. NO currebnt draw when in "B". For "B" you need to use the body shutter speed dial as the finders do not have a "B". Current draw on either of my two bodies is 2.15mA when the shutter is open on any other speed. If you leave the body shutter speed dial on the "red dot" and don't use a finder, the battery is always using 2.15mA for some reason.
    Possibly the 2nd option of battery removal is for those who don't have or forgot to bring a cable release? If the battery is out and you trip the shutter, it stays open until you either push the battery check button or switch speeds. That way you do not have to be an idiot and keep your finger on the shutter button for 45 minutes. :eek:)
    2. I've never seen that problem, and my two ancient bodies were bought off ebay. Sure sounds like something is not properly catching, latching or engaging.
    3. You'll be best served calling up Mamiya - or 917-347-3300 9AM-5PM EST in Elmsford, NY. Or you can try some other large camera store such as B&H, Adorama, etc.
    4.Can't help you with length. The "S" means that that was designed for the F2.8 lens and should not be used with the F1.9 lens as they "may" cause vignetting. It's in one of my various old Mamiya manuals.
    5. Don't know.
    6. Have never seen it personally. I own two bodies and 5 lenses in total. All bought at either cheap swap meets or off ebay.
    7. No idea, do not have one.
    Good luck with the fact finding mission.
    I enjoy using my M645 1000S's as light weight alternatives to my RB67's. The prices are dirt cheap. If you are having an issue with a body, it's probably cheaper to get another than to repair, although that's gambling again too.
  4. Teodor,
    • The 80 mm f/4 Macro has floating elements, you are right that you can see these rearrange when you change from "N" to "S".
    • The Macro spacer is 40 mm long. That's just a bit more than Auto-Extension Ring No. 3-S or No. 1 and 2 combined. If you don't mind that you will reach to a little less than 1:1 and the magnification scale at the front of the lens is slightly off, you can use your Auto-Extension Ring No. 3-S.
    • In the olden days, there was an Auto-Extension Ring No. 3 without the "S". That one was usable without vignetting only with the 80 mm f/2.8 lens, while the "S" version can also be used without vignetting with the 80 mm f/1.9 lens. This is what I got from Alexander Borell's book "Die Mamiya 645", which appeared in Hering Verlag, Germany in 1980. I am not sure if there is a translation of this book to English.
  5. OOPS ... if I could only read !
    "S" type are for the F1.9 lens, I reversed what I read in my mind. Christoph is quite correct. According to rereading this applies apparently only to the 3 ring, it makes no such statement about the shorter 1 and 2 ones.
    Copy of the page from the manual ...
  6. Thank you for your replies. This forum is very helpful, and I am grateful for your advice.
    Here are my thank-you notes for each question I had at the outset:
    1) It's good to know that the battery is not wasted in bulb. That's one thing less to worry about. The bulb setting works as it should, and it's wonderful to have that assurance.
    2) I have only observed the film advance irregularity with a blank 120 insert. I have not yet put actual film through the camera. It could be that the irregularity goes away completely when running film through the camera, but I have yet to confirm that. I bought two bodies from KEH. One came with a film advance crank, the other with a film advance knob. Both have the same behavior when I tested them with a blank 120 insert. Please try it with your camera in the same way to see if it shows the same behavior, and let me know what you find.
    3) Thank you for your suggestions about the focusing screens. I have checked with Adorama and B&H. The latter website lists a more recent product, Beattie Intenscreen, which is advertised as being brighter than the original Mamiya screens, so that persuaded me to change direction. I am going to get the Maxwell screen variations instead, even if that's more expensive than the original Mamiya screens. My reason: I have been using a Maxwell screen installed in a Rolleicord, and the new screen makes a big difference.
    4) and 5) Thank you for letting me know of the length of the Macro Spacer. It makes sense at first that the macro spacer is 40 mm long (half of 80 mm), but that still leaves me confused about how the lens achieves 1:1 magnification if the total extension in spacer mode is 23 mm (from the focusing helix) plus 40 mm (from the extension tube).
    I measured again the extension provided by the focusing helix of this lens:
    • switch ring set to N: displacement of 23.5 mm from infinity to half life size
    • switch ring set to S: displacement of 23.0 mm from half life size to full life size
    The optical design of this lens is obviously not the typical macro type. None of the principles that apply to macro lenses make any sense with this lens. I have no idea what to expect when I try to use this lens outside of its designed limits.
    How much extension would I need for a given level of magnification beyond 1:1? I would like to know that in advance rather than after the fact with an actual subject. This matters to me because the bellows factor might be completely different with this lens compared to my 100 mm f/4 Macro Takumar.
    Evidently the optical engineers at Mamiya designed the air spacing adjustment so as to provide good definition also for the non-macro focusing range. In other words, one could use this macro lens as a standard lens for regular focusing distances, without significantly worse picture quality compared to the 80 mm f/2.8 lens, although I would personally prefer the standard lens for that purpose because of the brighter maximum aperture and because of the wider focus throw.
    Also, it seems that this macro lens was specifically designed to be used in conjunction with the Macro Spacer from 1:2 to 1:1. Does it mean that the engineers expected that nobody would want to go beyond that limit? Well, I go beyond any such limits all the time in 35 mm. I see no reason to hold back with 645.
    I have no idea what mathematical function one would have to use to calculate in advance the amount of bellows extension (and thereby the amount of exposure correction) needed for this macro lens when going beyond 1:1.
    That's why I wish there was some kind of supplementary info in the user's manual, anything beyond the automatic instruction to buy the Macro Spacer like a mindless consumer. The Macro Spacer only applies to the range 1:2 to 1:1 anyway.
    6) I will upload a close-up picture showing the lens separation in the 300 mm lens I have. I am sending it back to KEH tomorrow for a refund because I cannot imagine being able to re-sell this lens later on to anyone if it turns out that I don't use the lens enough to justify keeping it. Even if the lens separation has no impact on the pictures, I still don't like the fact that I paid for a lens with the "LN-" rating and got an inferior sample instead. That's not to take away from the reputation of KEH. I am very happy with the quality, service and pricing of KEH. They just made a mistake in this one instance. We're just human after all. Nobody's perfect.
    7) I will upload some pictures of the bellows hood so you can see more easily what I mean about the scales.
    I am trying the M645 system because I bumped too many times into the limitations of the Rolleicord I have used:
    • only one focal length
    • portrait and tele photography require massive cropping, completely wiping out the whole point of using medium format over 35 mm
    • macro photography is not really possible (even with the Rolleinars)
    • square just doesn't suit me
    From my experience with 35mm equipment, I have found that outdoors I need to switch between a moderate wide angle, the standard lens and a tele lens. Indoors I need to switch between a moderate wide angle, the standard lens and the macro lens, occasionally with extension tubes to reach 1:1 magnification.
    The Rolleicord just does not have the flexibility of an SLR. It is permanently stuck with a moderate wide angle in 6x6, which becomes a standard focal length when cropped to 645.
    After applying genuine effort to become accustomed to the square format, I must admit to possessing little aptitude for composing for the square. Also, I find it wasteful to anticipate that a square negative will be cropped to 645. I just don't like that concept, even in principle. Since I put so much effort into composing carefully in the viewfinder, I would much rather compose with a camera that uses the 645 format from the outset.
    I am much happier when working with a rectangle than a square. There is one thing I'd like to share about that: I have noticed that the 1.5 aspect ratio of 35 mm is too skinny for vertical compositions. I expect that the 1.33 aspect ratio of 645 will be more suitable for that.
    I like very much that I can treat the Mamiya M645 as a cross between my 35mm SLR and a Rollei TLR (interchangeable lenses for ultimate flexibility combined with a decent waist level finder -- no more squinting into a tiny pentaprism viewfinder). I don't use flash, so the superiority of a leaf shutter over a focal plane shutter is of no consequence to me. To avoid the shake induced by the focal plane shutter, I use a rock solid tripod every time. (And to avoid the shake induced by the mirror slap, I use mirror lock-up every time.)
    I know that the Hasselblad is technically better than the Mamiya M645, but the prices charged for the Swedish brand, even for heavily abused second hand samples, are completely outside my purchasing power at this point in my life.
    Here's something to consider: So long as one has a good battery in the M645, the electronic focal plane shutter will be more accurate than any mechanical leaf shutter. From the research I have done, I am rather disappointed to learn that a leaf shutter simply does not provide the official shutter speeds that are engraved on it, only an approximation to them (within a 30% tolerance band), and you have to test the speeds yourself with slide film to discover the actual speeds of your particular leaf shutter. Not a nice fact in my opinion.
    The only downside with the shutter of the M645 is that it locks up in seriously freezing temperatures. That's no hindrance to me because I never do photography below -10 Celsius. Doesn't a Compur shutter in a Hasselblad have the same problem? The lubricants inside a mechanical leaf shutter must be affected by the cold too.
    On a more practical note, I would just not feel safe carrying a shiny, sexy-looking and instantly recognizable brand like Hasselblad in the street. I would much rather use equipment which is NOT valued by thieves.
    One should not overlook the availability of the tilt-shift macro bellows for the Mamiya M645. That option (together with the relative affordability of this system) is what convinced me to go for the Mamiya M645 over any other 645 system. (I had already ruled out the 6x7 cameras because they're too heavy and from twice to four times as expensive.)
    I intend to mount a large format lens of focal length 127 mm or 135 mm to the Mamiya bellows unit (with the help of S K Grimes), so I can try out tilts and shifts at all focusing distances without going into large format yet. I know that such a rig is a poor substitute for a purpose-designed tool like a 4x5 monorail, but then again, as with the Hasselblad, I cannot afford large format either.
  7. Here is the lens diagram for the 300 mm f/5.6 lens taken from the user's manual. The separation is between the first and second element of the front.
  8. The separation as seen from the front:
  9. The separation as seen from the front (with the lens slightly rotated about its axis):
  10. The lens separation as seen through the lens from the rear:
  11. Close-up of the separation, again from the front:
  12. The right hand scale of the bellows hood:
  13. The right hand scale of the bellows hood (with bellows fully extended):
  14. The left hand scale of the bellows hood:
  15. I just tested the camera with film. (I sacrificed two rolls of Ilford FP4, one for each camera body.) The film advance mechanism works exactly as advertised in the user's manual: one 360 degree rotation of the crank/knob advances one frame. So the behaviour with a blank 120 insert can be safely ignored.
  16. Just for reference, these are the extensions provided by the macro tubes (for some reason not provided by the user's manual):
    • 3-S: 35 mm
    • 2: 23.5 mm
    • 1: 12 mm
    So this is the total extension one can obtain by combining them:
    • 2 + 1: 35.5 mm (too short from 40 mm by 4.5 mm)
    • 3 + 1: 47 mm (too long from 40 mm by 7 mm)
    • 3 + 2: 58.5 mm
    • 3 + 2 + 1: 70.5 mm
  17. Lens separation can happen with any brand, I don't think it's particularly common to Mamiya 645 glass.
    As for those numbers on the bellows shade. Most people simply eyeball adjust the shade for vignetting through the viewfinder. I back it up just out of view in the frame. And then back it a tiny amount more to be safe.
    Regarding the screens. The Beattie screens are bright, but are more difficult to focus than the factory screen. The Maxwell screen is both bright and easy to focus.
  18. Teodor,
    there is a 150, 210, 300 mask for the bellows, so that explains why these numbers are interleaved with the others. Mamiya sort of put two scales into one there I guess.
    The other side looks like it has something to do with a slide copying setup, but that's just my guess.
  19. Butkus to the rescue!
    "Due to its large aperture, the Bellows Lens Hood extension of the 210 mm lens is shorter than the marked point of the 150 mm lens, to eliminate vignetting at its maximum opening."
    It still does not make sense!
    Both lenses (210 mm and 150 mm) have the same maximum aperture: f/4. Furthermore, both lenses have the same filter thread: 58 mm.
  20. Concerning the bellows extension of the 80 mm f/4 macro lens, I figured it out.
    Textbooks usually state that measuring the dimensions of the subject with a tape measure or ruler and calculating the magnification relative to the film format is equivalent to measuring the total amount of bellows extension (distance from the lens to the film plane).
    That rule holds for these two lenses:
    • 100 mm f/4 Macro Takumar for 35 mm
    • 135 mm f/4 Pentax Macro for 6x7
    For those two lenses, the standard table of exposure correction applies without any trouble:
    magnification delta EV total bellows extension
    (1/4):1 0.5 1.25 * f
    (1/2):1 1 1.5 * f
    (3/4):1 1.5 1.75 * f
    1:1 2 2 * f (double extension)
    2:1 3 3 * f (triple extension)
    3:1 4 4 * f
    4:1 4.5 5 * f
    5:1 5 6 * f
    6:1 5.5 7 * f
    f = focal length of the lens.
    Single extension corresponds to the lens being focused at infinity, in which the distance from the lens to the film plane is f.
    Here is what happens with the Mamiya-Sekor 80 mm f/4 macro lens (with floating elements) for the M645 (with the most significant data rows highlighted):
    mode = N
    displacement from infinity focus total bellows extension total bellows extension magnification expected total bellows extension (as measured on the 100 mm f/4 lens)
    10 4.5 mm 84.5 mm 1.056 * f 10 1.095 * f
    8 6 mm 86 mm 1.075 * f 8 1.1125 * f
    6 8 mm 88 mm 1.100 * f 6 1.1165 * f
    5 9.5 mm 89.5 mm 1.119 * f 5 1.1195 * f
    4 12 mm 92 mm 1.150 * f 4 1.24 * f
    3 16 mm 96 mm 1.200 * f 3 1.325 * f
    2.5 19 mm 99 mm 1.238 * f 2.5 1.39 * f
    2 25 mm 105 mm 1.313 * f 2 1.49 * f
    mode = S
    (assuming that the length of the Macro Spacer is 40 mm)
    magnification displacement from infinity focus total bellows extension total bellows extension magnification expected total bellows extension (taken from the standard table above)
    40 mm 120 mm 1.5 * f 2 1.5 * f
    1.7 44 mm 124 mm 1.55 * f
    1.5 47 mm 127 mm 1.59 * f
    1.25 53.5 mm 133.5 mm 1.67 * f
    1.1 57.5 mm 137.5 mm 1.72 * f
    1 63.5 mm 143.5 mm 1.79 * f 1 2 * f
    And here is a condensed table that shows just the salient features of the Mamiya macro lens:
    magnification total bellows extension expected total bellows extension
    (1/4):1 mode = N 1.150 * f 1.25 * f
    (1/2):1 mode = N 1.313 * f 1.5 * f
    (1/2):1 mode = S 1.5 * f 1.5 * f
    1:1 mode = S 1.79 * f 2 * f
    The curious consequences of the floating element design of this lens are two-fold:
    1. There are two bellows extensions for the half life size magnification to be aware of.
    2. At the beginning of each focusing range (namely the infinity focus mark for Mode = N and the half life size mark for mode = S), the total bellows extension matches that of any other standard macro lens, but at the end of each range (namely the half life size mark for mode = N and the full life size mark for mode = S), the exposure correction is approximately half a stop less than one would expect.
    At the end of the focusing range of mode = N (half life size), the lens has actual extension 1.313 * f instead of the expected extension 1.50 * f. Looking up in the exposure correction table above (and ignoring the magnification column), we see that:
    • 1.50 * f implies delta EV = 1.0
    • 1.25 * f implies delta EV = 0.5
    Similarly, at the end of the focusing range of mode = S (ful life size), the lens has actual extension 1.79 * f instead of the expected extension 2.00 * f. Looking up in the exposure correction table above (and ignoring the magnification column), we see that:
    • 2.00 * f implies delta EV = 2.0
    • 1.75 * f implies delta EV = 1.5
    In conclusion: When using the Mamiya-Sekor 80 mm f/4 Macro lens with floating elements, for the purposes of calculating the exposure correction, one must ignore the magnification and rely only on the bellows extension.

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