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Need help to identify mount on JCP 135mm f2.8
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PostPosted: Wed Feb 23, 2022 7:36 pm    Post subject: Need help to identify mount on JCP 135mm f2.8 Reply with quote
I'm back...

I have another lens that I just picked up for parts to fix another 135mm f2.8 when I realized the new one is actually in better shape. I just don't know the mount yet.
Anybody have an idea what this one is? Note the little tab on the side..
#1


#2



Thanks,

CN


PostPosted: Wed Feb 23, 2022 7:43 pm    Post subject: Reply with quote
Guessing Minolta.

The old standby guide to lens mounts with photos is http://rick_oleson.tripod.com/index-99.html

If you don't already know about Camera Register Distance which is important to know when adapting to retain infinity focus, basically your camera distance must be less than the original lens' camera distance to allow for adapter thickness, otherwise adapter thickness acts just like extension ring used for macrophotography, i.e., for closer focus. Wikipedia has a good list...


PostPosted: Wed Feb 23, 2022 9:14 pm    Post subject: Reply with quote
100% Minolta SR mount.

This lens has the MC tab for meter-coupling (introduced with Minolta SRT series cameras in 1966), but it doesn't have the later MD tab to allow for shutter-speed priority (introduced with the Minolta XD7/XD11 in 1977).

So, Minolta SR mount, MC generation, produced guaranteed after 1966 and very likely before 1977.


PostPosted: Wed Feb 23, 2022 11:30 pm    Post subject: Reply with quote
All, I appreciate the input, but I may be a bit confused.

I'm seeing an Minolta MD to M43 adapter on Amazon, for my M43 G9 camera (on order) but I can't find an SR adapter. Is this the same thing?
Also, doesn't the adapter take into account the infinity focus? Or am I "losing" some focus?

And that webpage with the pics of the mounts is now on my favorites tab! Great web page!

Thanks,

CN


PostPosted: Wed Feb 23, 2022 11:42 pm    Post subject: Reply with quote
Cheesenacho wrote:
All, I appreciate the input, but I may be a bit confused.

I'm seeing an Minolta MD to M43 adapter on Amazon, for my M43 G9 camera (on order) but I can't find an SR adapter. Is this the same thing?
Also, doesn't the adapter take into account the infinity focus? Or am I "losing" some focus?

And that webpage with the pics of the mounts is now on my favorites tab! Great web page!

Thanks,

CN


Ebay has adapters for "Minolta SR MD lens to M43 camera".

If camera for which lens was designed has longer register distance than your camera, the adapter will permit infinity focus (no loss of focus range). While there adapters for lenses designed for shorter register distance cameras, they permit only closer focusing if at all unless they have image degrading internal elements.

https://www.graphics.cornell.edu/~westin/misc/mounts-by-register.html


PostPosted: Thu Feb 24, 2022 12:53 am    Post subject: Reply with quote
Thank you very much. This was extremely informative to me.

CN


PostPosted: Thu Feb 24, 2022 1:45 am    Post subject: Reply with quote
Just a bit of additional info for you -- Minolta's first SLRs had the SR mount. It had no meter coupling. Next was the MC mount, which did have a single tab on the aperture ring that engaged a similar tab concentric to the lens mount, which engaged the MC camera's meter. Finally, there was the MD mount, which had an additional tab used to engage the program function on cameras with a program mode. Latest MD lenses have a latch on that MD tab that locks it into Program mode, so it won't be inadvertently bumped off.

When it comes to using manual focus Minolta lenses with other makes of cameras, like Canon's MF cameras, Minolta's MF cameras have a rather narrow depth between the lens flange and the film plane. Most cameras have a deeper measurement here, and as a result, infinity focus is lost when an adapter is used. You'll want to read the descriptions carefully for any adapter you buy. To achieve infinity focus, these adapters will have a correction lens, which usually degrades the image by a noticeable amount.


PostPosted: Thu Feb 24, 2022 9:58 am    Post subject: Reply with quote
cooltouch wrote:
Just a bit of additional info for you -- Minolta's first SLRs had the SR mount. It had no meter coupling. Next was the MC mount, which did have a single tab on the aperture ring that engaged a similar tab concentric to the lens mount, which engaged the MC camera's meter. Finally, there was the MD mount, which had an additional tab used to engage the program function on cameras with a program mode. Latest MD lenses have a latch on that MD tab that locks it into Program mode, so it won't be inadvertently bumped off.


Almost. Minolta's mount for their manual focus SLR cameras has always been the SR mount.

There are three generations of the SR mount:

1. SR, with automatic aperture control
2. SR, with automatic aperture control and MC tab for meter-coupling
3. SR, with automatic aperture control, MC tab for meter coupling, and MD tab for minimum aperture communication

Colloquially, these are referred to as the SR mount, MC mount, and MD mount, but technically that is incorrect, they are all generations of the SR mount.

Ignoring some details only relevant to collectors & Minolta fans, Minolta made five different lens lines for the SR mount (collectors' sub-classification in brackets):

ROKKOR (SR): also known as SR lens line; early budget preset lenses omitting automatic aperture control
AUTO ROKKOR (AR I, AR II, AR C): lenses enabling full automatic aperture control
MC ROKKOR (MC I,MC II,MC-X): lenses with automatic aperture control & meter coupling
MD ROKKOR (MD I,MD II): lenses with automatic aperture control, meter coupling, and minimum aperture communication
MD (MD III) : lenses with automatic aperture control, meter coupling, and minimum aperture communication; the final, more compact & lightweight generation of lenses where the ROKKOR name was dropped

All five generations of lenses will fit on all three generation SR lens mount. Depending on the combination you may lose meter coupling and/or program/shutter priority mode, but the lenses will always fit. The very first, very early AUTO ROKKOR lenses have a longer travel of the aperture control pin, hence the aperture won't fully open unless used on the contemporary earliest SR cameras (SR-2 and early SR-1).

Some additional info on: https://en.wikipedia.org/wiki/Minolta_SR-mount
Respected list of classifications compiled by Dennis Lohmann: http://minolta.eazypix.de/lenses/


PostPosted: Thu Feb 24, 2022 10:50 am    Post subject: Reply with quote
visualopsins wrote:

If camera for which lens was designed has longer register distance than your camera, the adapter will permit infinity focus (no loss of focus range). While there adapters for lenses designed for shorter register distance cameras, they permit only closer focusing if at all unless they have image degrading internal elements.

https://www.graphics.cornell.edu/~westin/misc/mounts-by-register.html


I would take that table with a pinch of salt; register distance is supposed to be from the mount to the film plane, but for Minolta they list the register distance between the mount and the pressure plate. It will give you a broad picture though.

For Minolta (SR mount) the value should be:

43.70mm (+0.03mm/-0.00mm) to the pressure plate
43.57mm (+0.01mm/-0.01mm) to the film plane for MC 50/1.7 & MC 50/1.4

The register ("flange back distance") for Minolta's lenses varies a little bit in their service manuals, presumably to allow for an optimised setting given residual field curvature and/or SA.

e.g. from Minolta's own service manuals:

43.56mm - 43.58mm (MC 50/1.7 & MC 50/1.4 )
43.58mm - 43.61mm (MC 17mm f/4 )
43.57mm - 43.59mm (MC 24mm f/2.8 )
43.55mm - 43.57mm (MC 28mm f/2 )
43.57mm - 43.60mm (MC 28mm f/2.8 )
43.59mm - 43.62mm (MC 28mm f/3.5 )
43.56mm - 43.59mm (MC 35mm f/2.8 )
etc.


PostPosted: Thu Feb 24, 2022 12:09 pm    Post subject: Reply with quote
RokkorDoctor wrote:
cooltouch wrote:
Just a bit of additional info for you -- Minolta's first SLRs had the SR mount. It had no meter coupling. Next was the MC mount, which did have a single tab on the aperture ring that engaged a similar tab concentric to the lens mount, which engaged the MC camera's meter. Finally, there was the MD mount, which had an additional tab used to engage the program function on cameras with a program mode. Latest MD lenses have a latch on that MD tab that locks it into Program mode, so it won't be inadvertently bumped off.


Almost. Minolta's mount for their manual focus SLR cameras has always been the SR mount.

There are three generations of the SR mount:

1. SR, with automatic aperture control
2. SR, with automatic aperture control and MC tab for meter-coupling
3. SR, with automatic aperture control, MC tab for meter coupling, and MD tab for minimum aperture communication


Absolutely correct, of course. I was perhaps oversimplifying a bit. Except I would add that, while the MD tab does indicate minimum aperture, this is also the setting where the Program mode is engaged on cameras that support this function.


PostPosted: Thu Feb 24, 2022 8:51 pm    Post subject: Reply with quote
Wow! Tons of information here from the experts. I appreciate the detail.

Just waiting on an adapter to get and the first thing I'm going to check is infinity focus.

Thanks again,

Jeff


PostPosted: Fri Feb 25, 2022 4:08 pm    Post subject: Reply with quote
Minolta SR bayonet. The tab on the side indicated that its for MD mount cameras


PostPosted: Fri Feb 25, 2022 4:16 pm    Post subject: Reply with quote
philslizzy wrote:
Minolta SR bayonet. The tab on the side indicated that its for MD mount cameras


No MD tab on that lens, only the MC tab.

It will support meter-coupling on SRT/XE/XK/XD/XG/X cameras, but not shutter-speed priority or program operation on e.g. XD7/11 or X700.


PostPosted: Fri Feb 25, 2022 6:32 pm    Post subject: Reply with quote
RokkorDoctor wrote:
visualopsins wrote:

If camera for which lens was designed has longer register distance than your camera, the adapter will permit infinity focus (no loss of focus range). While there adapters for lenses designed for shorter register distance cameras, they permit only closer focusing if at all unless they have image degrading internal elements.

https://www.graphics.cornell.edu/~westin/misc/mounts-by-register.html


I would take that table with a pinch of salt; register distance is supposed to be from the mount to the film plane, but for Minolta they list the register distance between the mount and the pressure plate. It will give you a broad picture though.

For Minolta (SR mount) the value should be:

43.70mm (+0.03mm/-0.00mm) to the pressure plate
43.57mm (+0.01mm/-0.01mm) to the film plane for MC 50/1.7 & MC 50/1.4

The register ("flange back distance") for Minolta's lenses varies a little bit in their service manuals, presumably to allow for an optimised setting given residual field curvature and/or SA.

e.g. from Minolta's own service manuals:

43.56mm - 43.58mm (MC 50/1.7 & MC 50/1.4 )
43.58mm - 43.61mm (MC 17mm f/4 )
43.57mm - 43.59mm (MC 24mm f/2.8 )
43.55mm - 43.57mm (MC 28mm f/2 )
43.57mm - 43.60mm (MC 28mm f/2.8 )
43.59mm - 43.62mm (MC 28mm f/3.5 )
43.56mm - 43.59mm (MC 35mm f/2.8 )
etc.


And for the MD III 35-70mm 3.5 macro?


PostPosted: Fri Feb 25, 2022 10:01 pm    Post subject: Reply with quote
Ernst Dinkla wrote:
And for the MD III 35-70mm 3.5 macro?


Sorry Ernst, I only have the service manuals for a select number of MC Rokkor lenses, no MD Rokkor lenses. This was just to illustrate that there is some (slight) variation amongst the flange back distances specified in the Minolta service manuals.

Register distance is a bit of an "inexact science" with 35mm cameras anyway, and really only refers to nominal measurements. Bear in mind that 35mm film thickness is somewhere around 0.13mm-0.15mm, and the film channel between the film guides and pressure plate is around 0.2mm in many cameras I believe, the film therefore has around 0.05mm-0.07mm free space. That is to avoid clamping, sticking, and scratching issues given the unavoidable variability in film thickness between brands, production batches and possibly even humidity levels.

Calculating back from the 43.70mm register-to-pressure-plate spec for the Minolta SR mount, the emulsion of the film could therefore be positioned anywhere from 43.50mm to 43.57mm. Hence film-flatness has always been an issue on 35mm cameras (and 120 format cameras, except e.g. the CONTAX RTS III with its vacuum back). Consequently, with many film cameras there can be noticeable inconsistency in the frame-to-frame focus accuracy when shooting at fast stops like f/1.4 and f/1.2.

Although slightly dated, Camera Technology, The Dark Side of the Lens, Norman Goldberg, Academic Press, 1992, has an interesting chapter on film flatness issues.


Helaas, Ernst, kan ik je de register afstand voor de 35-70mm macro niet bevestigen Sad


PostPosted: Sat Feb 26, 2022 1:57 am    Post subject: Reply with quote
I find this level of detail between you experts fascinating.

So, is there a preferred adapter, from eBay or other source that will guarantee infinity focus on a LUMIX G9 M43 camera?

The adapter I had ordered on Amazon from Fotasy got here this evening and I am going to run some infinity tests tomorrow.

Jeff


PostPosted: Sat Feb 26, 2022 11:37 am    Post subject: Reply with quote
RokkorDoctor wrote:
Ernst Dinkla wrote:
And for the MD III 35-70mm 3.5 macro?


Sorry Ernst, I only have the service manuals for a select number of MC Rokkor lenses, no MD Rokkor lenses. This was just to illustrate that there is some (slight) variation amongst the flange back distances specified in the Minolta service manuals.

Register distance is a bit of an "inexact science" with 35mm cameras anyway, and really only refers to nominal measurements. Bear in mind that 35mm film thickness is somewhere around 0.13mm-0.15mm, and the film channel between the film guides and pressure plate is around 0.2mm in many cameras I believe, the film therefore has around 0.05mm-0.07mm free space. That is to avoid clamping, sticking, and scratching issues given the unavoidable variability in film thickness between brands, production batches and possibly even humidity levels.

Calculating back from the 43.70mm register-to-pressure-plate spec for the Minolta SR mount, the emulsion of the film could therefore be positioned anywhere from 43.50mm to 43.57mm. Hence film-flatness has always been an issue on 35mm cameras (and 120 format cameras, except e.g. the CONTAX RTS III with its vacuum back). Consequently, with many film cameras there can be noticeable inconsistency in the frame-to-frame focus accuracy when shooting at fast stops like f/1.4 and f/1.2.

Although slightly dated, Camera Technology, The Dark Side of the Lens, Norman Goldberg, Academic Press, 1992, has an interesting chapter on film flatness issues.


Helaas, Ernst, kan ik je de register afstand voor de 35-70mm macro niet bevestigen Sad


Dank je wel.

The adaptations I made of MD lens mounts to either EF or FE mount were based on a basic 43.50mm SR register distance but in the end the infinity calibration was done in the lens itself to a DIY collimator.
Calibrated on one digital mirrorless camera with or without the additional (EF<>FE) adapter. EVF + my eye should deal in practice with field curvature. I did not not notice that issue in the few MDs that I have. That is all fine for lenses without independently moving elements/groups.
The 35-70mm is of course in another category, a zoom lens. It got a conversion to EF mount. So I removed a brass tweaking ring near the mount that was 0.5mm thick, thinner ones there too which were kept in place. After that infinity calibrated at the front group and it matched the knife scratch that I put there before starting this change. I doubt I could do better by removing one of the other tweaking rings.

Film bulging: Vacuum systems have been used on more backs. Static electricity on stationary equipment, with obvious risks. IIRC the MF format Koni Rapid Omega clamped the film in rest and released the plate first before advancing the film. Rebuild MF Linhof backs on Alpa cameras had the 645 film frames placed lengthwise on 120/220 film and way more unused film area around it for clamping, which also improved handling and flatness afterwards in enlargers etc. I used magnetic vinyl masks, hand cut, for film mounting in scanners, odd film formats and SX70 Polaroid shots to avoid newton rings. Worked well. Thought about magnetic vinyl film envelops 4x5 for a Polaroid Pathfinder 110 where the DIY conversion to Polaroid sheet film became obsolete too in time.

Thank God we have sensors now.

Met vriendelijke groet, Ernst


PostPosted: Sat Feb 26, 2022 12:31 pm    Post subject: Reply with quote
Ernst Dinkla wrote:
Dank je wel.

The adaptations I made of MD lens mounts to either EF or FE mount were based on a basic 43.50mm SR register distance but in the end the infinity calibration was done in the lens itself to a DIY collimator.
Calibrated on one digital mirrorless camera with or without the additional (EF<>FE) adapter. EVF + my eye should deal in practice with field curvature. I did not not notice that issue in the few MDs that I have. That is all fine for lenses without independently moving elements/groups.
The 35-70mm is of course in another category, a zoom lens. It got a conversion to EF mount. So I removed a brass tweaking ring near the mount that was 0.5mm thick, thinner ones there too which were kept in place. After that infinity calibrated at the front group and it matched the knife scratch that I put there before starting this change. I doubt I could do better by removing one of the other tweaking rings.


You likely got that one converted fine, especially if it is still par-focal after your tweak.

I always keep the Minolta SR - SONY E mount adapters on my SONYs. I therefore only needed to do the infinity adjustment on those adapters the once. Any non-SR mount lenses I converted to SR-mount lenses rather than directly to E-mount, so they can also go straight onto the same adapter.

You may have seen my other posts on that:

http://forum.mflenses.com/diy-dust-seal-in-adapter-for-mirrorless-camera-t83466.html

http://forum.mflenses.com/custom-minolta-sr-md-mount-adaptations-t83467.html

For collimation I have found that compared to a DIY collimator, in practice a few known good film bodies (correct mount register & correctly adjusted focus screen) using the split wedge, a distant sharp vertical high-contrast object, and a viewfinder magnifier works just as well. Some folks put the focus screen across the film guides to ensure correct focus screen positioning, but that is not necessarily any good; because of the Fresnel screen pressed into the focus screen, the correct point of focus is not exactly on the surface of the screen, plus there is the 50 microns or so film gap as discussed.

I did of course check the register on my Minolta film bodies with a vernier depth gauge. However, since I have a very large collection of Minolta SR mount lenses, simple statistics become useful as well. If, across 200+ lenses which had never been serviced after they left the factory when I got them, a body has infinity focus spot-on for something like 90% of them, with the remaining 10% focussing just marginally short or long, I have to assume the body is good (enough) Smile

As for the distant object used; I go conservative; 10,000 x focal length: 500m for a 50mm lens, 5km for a 500mm lens. Yes, the latter requires a short walk from here from where I can see the nearest major town 6 miles away.

Ernst Dinkla wrote:
Thank God we have sensors now.


And, with mirrorless, no mirror that can get misaligned Wink


PostPosted: Sat Feb 26, 2022 5:31 pm    Post subject: Reply with quote
RokkorDoctor wrote:

Although slightly dated, Camera Technology, The Dark Side of the Lens, Norman Goldberg, Academic Press, 1992, has an interesting chapter on film flatness issues.


Hey Mark, I haven't dug out my copy of Joseph D. Cooper's two-volume set on Minolta, so I don't know if he has any discussion on the Minolta film plane specs, other than probably mentioning the official number, I suppose.

I realize this is drifting far afield of the original topic, but I'll mention this briefly. Speaking of Cooper, his books are a pretty cool insight into camera and lens tech at the time they were published. He authored two two-volume sets that I know of: Nikon and Minolta. I have both. My Minolta set is a second edition with a copyright date of 1976, so it is a very useful reference for Minolta gear dating from that time and prior.
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