p.14 #1 · A thinner sensor stack may be possible after all!
Tariq Gibran wrote:
Perhaps I'm not following but I thought Douglas was referring to focus shift, which is a real issue with a number of classic rangefinder lenses. Are you suggesting there is some sort of calibration of the rangefinder that somehow adjusts for focus shift at different apertures?
In my experience, some lenses cannot be well calibrated for both near and far distances. I don't know why exactly but that's a fact. Normally Leica will calibrate them for near distances and let the user use the infinity stop instead of the RF for far distances.
p.14 #2 · A thinner sensor stack may be possible after all!
edwardkaraa wrote:
In my experience, some lenses cannot be well calibrated for both near and far distances. I don't know why exactly but that's a fact. Normally Leica will calibrate them for near distances and let the user use the infinity stop instead of the RF for far distances.
p.14 #3 · A thinner sensor stack may be possible after all!
Tariq Gibran wrote:
Interesting. I did not know that.
I am wondering if this may also have to do with Leica having some of their longer R lenses (like the 280mm f4 Apo Telyt) and some R zoom lenses (like I believe the newer 80-200mm f4 Vario Elmar lens) focus past infinity. My understanding is that in that case it was to allow for differences caused by temperature so you would focus at whatever distance adjustment necessary for the circumstances.
p.14 #4 · A thinner sensor stack may be possible after all!
Tariq Gibran wrote:
Perhaps I'm not following but I thought Douglas was referring to focus shift, which is a real issue with a number of classic rangefinder lenses. Are you suggesting there is some sort of calibration of the rangefinder that somehow adjusts for focus shift at different apertures?
The ZM 50/1.5 the most famous case in point and there are two camps. One group could not take it and either did not buy or sold the lens. The other sizable group learned to adjust their focus and love the lens. Some even had the calibration optimized for wide open shooting at a particular distance.
p.14 #5 · A thinner sensor stack may be possible after all!
And rangefinder focusing foibles (of which there are many - and I love my ZM 50/1.5!) are all addressed by live view focusing. So, while the Sony and others of it's ilk have tradeoffs vs. classical rangefinder cameras that some love and others love to hate, we're all veering rather off-topic on this thread.
p.14 #6 · A thinner sensor stack may be possible after all!
mdemeyer wrote:
So, the dilemma... What should Kolari adjust focus for?
Would it not make the most sense to place the sensor at the exact specification set by Sony for the optical infinity setting (using the calculated amount to take into account the physical vs optical difference) and let all the various adapters fall where they might (with the perfect ones being bang on)? ...or is it not possible to calculate the exact amount needed for physical adjustment?
p.14 #7 · A thinner sensor stack may be possible after all!
Whether achieved by math, theory, or practice, I believe that is what has been done.
My original comment on the infinity focus topic was in response to those who were voicing concerns that it focused past infinity. I wanted to make sure people understand that there is not a perfect way to address this when people use a variety of adapters.
I was also curious if people would prefer to standardize on one adapter in exchange for precise infinity focus with properly calibrated lenses. Or my more extreme thought of replacing the Sony mount in its entirety with a custom M mount, eliminating the adapter entirely at the expense of E mount lens compatibility.
p.14 #8 · A thinner sensor stack may be possible after all!
Tariq Gibran wrote:
Would it not make the most sense to place the sensor at the exact specification set by Sony for the optical infinity setting (using the calculated amount to take into account the physical vs optical difference) and let all the various adapters fall where they might (with the perfect ones being bang on)? ...or is it not possible to calculate the exact amount needed for physical adjustment?
One annoying aspect of all Sony AF glass which can be attached to the A7 cameras: no infinity stop.
They just make it so lifeless to MF any of their lenses. OK my 70400 feels good but still, no infinity stop!
mdemeyer wrote:
And rangefinder focusing foibles (of which there are many - and I love my ZM 50/1.5!) are all addressed by live view focusing. So, while the Sony and others of it's ilk have tradeoffs vs. classical rangefinder cameras that some love and others love to hate, we're all veering rather off-topic on this thread.
So I'll stop now and stay on track.
If you think this thread is OT you should have seen the original "RF wides on A7" thread which started right after the announcement of the A7 and went hundreds of pages before we even had the cameras!
These guys mostly predicted what ended up being true, but I refused to believe it, pending actual results. Epic battle So there is huge history on this subject here I first tried the A7r, but sent it back for smearing, then tried the A7, but finally just gave up and bought an M9
Meanwhile Edward who rightly dissed the Sony from the start, to my horror and indignation, had his own M9's sensor corrode, and actually bought and shot the A7 (very well), right when I started with the M9. What a flip flop!!!!
But that was only a short episode of insanity for Edward, and it was not long before he had a M240. Now, if only he could correct the colorcast of the ZM35/2
mdemeyer wrote:
I was also curious if people would prefer to standardize on one adapter in exchange for precise infinity focus with properly calibrated lenses. Or my more extreme thought of replacing the Sony mount in its entirety with a custom M mount, eliminating the adapter entirely at the expense of E mount lens compatibility.
Michael
M mount would be great, but it is cool to be able to shoot sony/minolta glass.
A really high tolerance M adapter with CF helicoid that is not heavy: the Hawks is close but it's hard too keep things really tight when you are hanging all sorts of heavy lenses on it all the time. The other fancy one....CV? is OK but heavy.
p.14 #9 · A thinner sensor stack may be possible after all!
uhoh7 wrote:
One annoying aspect of all Sony AF glass which can be attached to the A7 cameras: no infinity stop.
They just make it so lifeless to MF any of their lenses. OK my 70400 feels good but still, no infinity stop!
If you think this thread is OT you should have seen the original "RF wides on A7" thread which started right after the announcement of the A7 and went hundreds of pages before we even had the cameras!
These guys mostly predicted what ended up being true, but I refused to believe it, pending actual results. Epic battle So there is huge history on this subject here I first tried the A7r, but sent it back for smearing, then tried the A7, but finally just gave up and bought an M9
Meanwhile Edward who rightly dissed the Sony from the start, to my horror and indignation, had his own M9's sensor corrode, and actually bought and shot the A7 (very well), right when I started with the M9. What a flip flop!!!!
But that was only a short episode of insanity for Edward, and it was not long before he had a M240. Now, if only he could correct the colorcast of the ZM35/2
M mount would be great, but it is cool to be able to shoot sony/minolta glass.
A really high tolerance M adapter with CF helicoid that is not heavy: the Hawks is close but it's hard too keep things really tight when you are hanging all sorts of heavy lenses on it all the time. The other fancy one....CV? is OK but heavy. ...Show more →
Charlie,
There are also the Phigment adapters that offer many advantages, but at present vignettes for about 75mm M mount lenses and longer due to its being designed prior to the release of the FF A7 series cameras. Paul is considering offering a newer adapter to deal with the vignetting for the FF cameras as well as one as a Helicoid, but as yet these are still only being considered for manufacture.
p.14 #10 · A thinner sensor stack may be possible after all!
mdemeyer wrote:
Whether achieved by math, theory, or practice, I believe that is what has been done.
My original comment on the infinity focus topic was in response to those who were voicing concerns that it focused past infinity. I wanted to make sure people understand that there is not a perfect way to address this when people use a variety of adapters.
I was also curious if people would prefer to standardize on one adapter in exchange for precise infinity focus with properly calibrated lenses. Or my more extreme thought of replacing the Sony mount in its entirety with a custom M mount, eliminating the adapter entirely at the expense of E mount lens compatibility.
Many thanks for persevering and finding a supplier that was prepared to put in the effort and research needed to make the conversion happen. I had approached a couple of other similar suppliers a few months ago but they were not prepared to put the effort required in - particularly re-adjusting infinity focus.
My Sony A7R is on its way to Kolarivision from the UK and I hope to be able to start using my collection of 12 Leica M mount lenses soon. Will post test images as soon as I get it back next month.
I don't expect miracles but was about to sell the Sony A7R before this as it had been gathering dust after purchasing a Leica M240.
I use the Metabones adaptor and would rather that lenses focus very slightly past infinity when I get it back from Ilija and his team as I can very easily correct for that. Not being able to reach infinity focus and having to send the camera back even if it did just affect a couple of lenses would be far more devastating.
p.14 #12 · A thinner sensor stack may be possible after all!
uhoh7 wrote:
A really high tolerance M adapter with CF helicoid that is not heavy: the Hawks is close but it's hard too keep things really tight when you are hanging all sorts of heavy lenses on it all the time. The other fancy one....CV? is OK but heavy.
I bought and returned the most recent version of the Hawks helicoid adapter as I found that with the heavier and longer lenses, it was almost impossible to turn the helicoid. With light, short lenses it worked great though. Not sure if the issue I experienced was somehow part of the design but it does limit it somewhat.
p.14 #13 · A thinner sensor stack may be possible after all!
Tariq Gibran wrote:
I bought and returned the most recent version of the Hawks helicoid adapter as I found that with the heavier and longer lenses, it was almost impossible to turn the helicoid. With light, short lenses it worked great though. Not sure if the issue I experienced was somehow part of the design but it does limit it somewhat.
It's definitely not smooth but the combination of helicoid, infinity adjustment and reasonably priced is hard to pass. The problem with helicoid I have also seen so far is the mount alignment issue. Since it contains two movable pieces, these adapters can cause a similar effect as lens de-centering. I remember reading a post somewhere that a user compared a whole bunch of L-E adapters for alignment issue. He concluded that both the CV and Hawk's have problem and his Novoflex maintains good flatness. I observed a mild mis-alignment (at 100% pixel-peep with careful back and forth check) developing on my Hawk's V.3 over the short time that my ZM 15 was on it (less than 6 months).
p.14 #14 · A thinner sensor stack may be possible after all!
hiepphotog wrote:
Since it contains two movable pieces, these adapters can cause a similar effect as lens de-centering.
All manual lenses have helicoids themselves though. Strange that Cosina wouldn't be able to (or doesn't want to) make a helicoid with precise tolerances for this then.
From the demonstration of the coffee cup icon, the ZM 35/2 on the M9 still yields less smearing than the Loxia 35 on the A7r, disregard a little blown-out highlight at the bottom left crop of the M9 shot. From the interview, it seems like retrofocal lens might benefit the most, IMO. Symmetric design might not fully recover due to very steep angle of light while telecentric might just not see much in improvement.
p.14 #16 · A thinner sensor stack may be possible after all!
AhamB wrote:
All manual lenses have helicoids themselves though. Strange that Cosina wouldn't be able to (or doesn't want to) make a helicoid with precise tolerances for this then.
The difference is lens helicoid has more contact surface area and the weight tend to distribute evenly along the lens.
p.14 #18 · A thinner sensor stack may be possible after all!
sebboh wrote:
+1
it's a lot harder to make a helicoid that doesn't shift with torque when it's as short as the hawk's. then of course there's the cost...
Seems like I read where the Hawks uses some sort of spring tension system. I believe the spring tension becomes greater as the attached lens weight increases. Perhaps this prevents the system from shifting but also causes the focusing action to become more difficult as the tension increases.
nice link and TY for that. But it's very superficial and stating what has been put forward from the lens introduction, no?
We've all learned the hard way how cover glass effects the edges and corners. So those diagrams simply show what we know, right?
We know zeiss designed the lens to perform better with the A7 sensor CG, because they said so at the beginning and because the wide ZMs show such smearing; they are going to have to change something.
What exactly did they change?
Why didn't they hit the ball out of the park with the Loxia 35 and their 2470 zoom?
You are way ahead of me in all this stuff, what do you think?
How was the Loxia 35/2 "specially adjusted" and why did it balloon into twice the size of the zm35/2?
Many feel now that the FE35/2.8 and FE55/1.8 make a more potent combo than the Loxias 35 and 50---they are just that good? The same was true of the 2870 zoom which is very close in performance to the 2470.
My own personal theory is that the FE lenses get more corrections from the processor, a feature hinted in the japanese interview with the A7 design team.
So there is huge history on this subject here 
