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Do lenses work differently on film and digital?

khiromu

New member
Hello

I am having a problem with one Lenca lens that I sold.

The lens was CLAed by Leica certified tech, and then sold to somebody. I just got an email from the buyer that the lens I sold is either not focusing correctly or not sharp until it is stopped down to F8. And I received those images, and I agree with the buyer's claim, images at wide open is terribly out of focus. I also received images taken with Summilux 50mm wide open and the image is very sharp.

Now, I have contacted the tech about this problem. Then I was asked which body is being used. I told the tech it is M9, and I also told that the M9 body focuses perfect with sharp image with the buyers other lenses. Now I was told that the problem is because the lens is used with digital body, and the tech suggested me to refund money, and sell it to somebody who shoots with films. Then, the lens should work fine.

Now, my question is if one lens does not work with M9, will it work fine with film body?

Anyway, I gave the buyer for options of either sending it back to me for refund, or send it to somebody such as DAG for another CLA.

Thank you for your help.
Hiromu
 

Jan Brittenson

Senior Subscriber Member
Some lenses show focus shifts - focus moves with aperture - on a digital camera. Not much to be done about that. The only lens I've personally run into that does it is the CV 40/1.4, but the effect is real. However, it doesn't sound like this is what's happening... it could be the buyer's M9 is out of calibration as well - if this is a 90 or 135, maybe even 75, and they haven't had a lens longer than 35-50 before, then they may simply not have noticed!
 

khiromu

New member
Thank you.
The lens having problem is Summicron 28mm, and the buyer's M9 works perfect with Summilux 50mm.
Hiromu
 

mathomas

Active member
I have read (in LFI, no less) that a digital sensor is so flat (essentially two-dimensional) that it shows focus shift problems much more easily than film. Film apparently has enough depth (though still obviously very shallow) that focus will possibly be good at some layer of the emulsion. I find it hard to believe that film's "depth" is enough to account for focus shift problems, but I have heard/read it more than once.

I'm sorry for your position. I've been on the other side: I bought a lens here on getdpi.com that focus-shifted on my M8. I also sent example photos to the seller, and he kindly and quickly refunded my money. It's the right thing to do, though painful and frustrating. (In this particular case, he actually reproduced the focus shift on his M9 after receiving the lens back. He had not noticed it in his prior use since he didn't shoot wide-open very much).
 

khiromu

New member
Thank you, Mike.

Yes, the buyer is returning the lens for refund.

I am aware of focus shifting with some other lenses such as Summilux ASPH 35mm (not the latest), but never with Summicron 28mm...

Well, once I receive the lens back, I will have to test with film body to check if it works...

Thank you.
Hiromu
 

Nettar

New member
I agree with you, Mike, that the problem is caused by the thickness of the emulsion. Of course, in black and white film there is generally only one light-sensitive (silver halide) layer, but in colour film there are several, representing different colours (e.g. blue, yellow, green, red). When using colour transparency medium-format film, with fast lenses, I had the impression (rightly or wrongly) that the colour tinges of out-of-focus areas depended on which layers the out-of-focus light rays struck. And for a film with a warm-colour layer on top you could make the picture slightly warmer by marginally under-exposing, so that a larger proportion of the light never made it through to the layers below. These experiences convinced me that the thickness of the emulsion in film, and the order in which the layers were placed in the case of colour film, were rather significant and important to the picture. In contrast, the sensor plane of a digital camera is of negligible thickness. Nettar
 
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Jan Brittenson

Senior Subscriber Member
The Summicron 28 though should have no issues - lots of people use it on both the M8 and M9. Chuck who frequently posts here has one and loves it on his M9. I'm inclined to think it wasn't properly reassembled...
 

khiromu

New member
Lenses not focusing with digital are fairly common -- here is one thread I found, re: sending to DAG for calibration.

http://forum.getdpi.com/forum/showthread.php?t=16580
I'm inclined to think it wasn't properly reassembled...
That's what I do not want to see since the Leica tech is often recommended by many people, but have to check out that possibility. So once I received the lens back from the buyer, I will check with my film Leica and see what I get. If the tech is right, then I should see good images on my negs. If not, then I have to send it back for another CLA.

Thank you.
Hiromu
 

jaapv

Subscriber Member
That tech does not know his job. Since 2006 Leica lenses need to be adjusted to narrower tolerances for reasons outlined above, and all competent technicians do that. Leica will return lenses nowadays " adjusted to M8/9 specifications" It is not rocket science...
 

Bill Caulfeild-Browne

Well-known member
I bought a 75 Cron asph from a reliable source who had had it cla'd before selling. It was front focussing badly on my M9 - but had not been on his!

We got it fixed under warranty and now it's fine. I can only assume that it was abused in transit to me by the PO which was enough to put it "off". All my other lenses are fine and now it is too.

Bill
 

Jerry_R

New member
Curiosity question - what would you do with M9 on warranty - if you would like to calibrate CV or ZEISS lens?

Solms states they only calibrate LEICA lenses.
 

thrice

Active member
Curiosity question - what would you do with M9 on warranty - if you would like to calibrate CV or ZEISS lens?

Solms states they only calibrate LEICA lenses.
Sherry Krauter and Don Goldberg both calibrate to M9 tolerance.

The issue here is NOT calibrating for digital OR film. They both have the same register distance. Only difference is that front focus won't be as visible on film due to the thickness of the film compensating slightly, VERY slightly.
 

D&A

Well-known member
I concur what others have expressed, namely the 28mm cron asph does not generally exhibit focus shift, nor is fussy, so if it was focus adjusted properly after a CLA, (and esepcially that it is a wide angle f2 lens), then the lens should focus properly on most any properly adjusted m8 and M9. Although you can test it by shooting it on a film body when you get the lens back, may I suggest that you try it also on any number of M8/M9 you might be able to try it on. If adjusted correctly, then it should focus correctly on most all of these bodies, if not, it may just be a simple case of needing simple focus adjustment by a qualified tech and then all should be fine.

Dave (D&A)
 

Chuck Jones

Subscriber Member
I wouldn't waste your time checking a 28mm 'Cron ASPH on film. Just go ahead and send It back for adjustment. It should make little to no difference. The 28 'Cron is a GREAT lens that focuses just fine on M8 or M9, and is tack sharp on both bodies, in my own experience. Having used it extensively on my M8 and a bit now on my M9 I give it two thumbs up for sure. One of the top four or five lenses made for a Leica M in my opinion. Clearly, your example is out of adjustment.
 

khiromu

New member
Clearly, your example is out of adjustment.
I hope that's the case. But I need to see it by myself before asking the tech for another CLA. Though, the tech did suggested me to simply re-sell to somebody who shoots films, rather than sending it back for another CLA...
 
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