Calibrated lens for M8

scorpius73

scorpius73

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I have the opportunitiy to purchase a Zeiss 35mm f2 ZM. I will be using it on my M6. It has been calibrated by DAG for the M8. Will that affect its focusing or anything on my M6? I didn't know where to post this question. So, I figured I would throw it to the Leica M8 users in this forum. Thanks.
__________________
 
I'm not as pessimistic as Fred, but I would be careful & get return privileges from the seller. Lenses, especially those for Leica mount, can vary as much as bodies so it can make perfect sense to adjust a lens to a body (assuming the body is to spec), so I disagree that it's necessarily "ruined."

Because of the flatness of the sensor, etc., usually the M8 is much more demanding of a lens than a film body, & many people, including myself, have @ least a few that don't perform as well on the M8 as they do on film bodies (i.e., they show noticeable front or backfocus on the M8). If that was the case w/your Biogon & DAG basically just brought it to spec, then it should work perfectly on your film bodies.

However, this seems to be more common w/vintage lenses that may never have been properly collimated in the 1st place, have focus shift that becomes more apparent on the M8, or were incorrectly reassembled/adjusted after being cleaned/repaired. I would think this would be less likely for an almost-new lens, especially from a good manufacturer like Zeiss/Cosina. Another situation that arises is w/lenses that have special curved cams for extra-accurate focusing, like the 75/1.4 Summilux, that can have problems w/various bodies (including the M8) due to subtle differences in the RF-to-lens linkage, but again that wouldn't likely apply to a 35 like the Biogon ZM.

If the seller has forgotten or isn't entirely forthcoming, you could get the serial # & call (not email) DAG & ask him what he actually did w/the lens.
 
After a bit of emailing

After a bit of emailing

This is what the seller told me.
"Don adjusts the lens so it has accurate focus @ f2 (maximum aperture) at the minimum focus distance. Exactly how he does it is beyond me.
I checked it when I got it back by taking a shot of a focus chart @f2 and the in focus line was sharp and right on.
The calibration is $90 and I had 3 lenses done. This one and my Hexanon-M 50 & 90mm's.
A lot of lenses either focus slightly in front of, or behind the spot you focus on, but you don't notice as higher f stops and distance give larger depth of field.
In 99% of the shots it's no big deal, but if you shoot close, wide open it does make a difference.
I also have a 50mm ZM f1.5 C-Sonnar that is calibrated for f2.8 from the factory. When I shoot @ f1.5, I have to focus slightly behind to get a sharp image. I did not get this one done even though the factory will re-calibrate it @ NC as I like it the way it is. The images have a dreamy quality that I really love. Larger than f4,it's as sharp as any lens out there.
Hope this explains it. It really was not a big issue with this lens, but I was sending the other two in and sent this on along. Used on a film camera as a 35mm lens, there would not be an issue at all, but on the M8, it becomes a 50mm and focus is more critical. You loose depth of field more at 50mm and above than 35 and below."
So, I think it will be fine.
 
Last edited:
Because of the flatness of the sensor, etc., usually the M8 is much more demanding of a lens than a film body, & many people, including myself, have @ least a few that don't perform as well on the M8 as they do on film bodies (i.e., they show noticeable front or backfocus on the M8). If that was the case w/your Biogon & DAG basically just brought it to spec, then it should work perfectly on your film bodies.
Click to expand...

Hi all,
The above Statement is exactly what Don told me.
He does quite a few lenses for that very reason.
I'm the seller of the lens in this thread and can tell you that it did make a difference. The 50 & 90 that I also had done are right on as well.
As we all know, the larger the focal length, the more you need the lens to be right on. All of the images I shot with the 3 lenses I had done are better for it, but the 90 shows it the most.
Here's one image from the 90mm cropped down.
The gull was quite a distance and focus was on the eye.
I highly recommend the calibration if you are an M8 shooter and because the M8 is more critical than film, you are the better for it either way
2947863450_94be601856_b.jpg
 
lewis44 said:
Hi all,
The above Statement is exactly what Don told me.
He does quite a few lenses for that very reason.
I'm the seller of the lens in this thread and can tell you that it did make a difference. The 50 & 90 that I also had done are right on as well.
As we all know, the larger the focal length, the more you need the lens to be right on. All of the images I shot with the 3 lenses I had done are better for it, but the 90 shows it the most.
Here's one image from the 90mm cropped down.
The gull was quite a distance and focus was on the eye.
I highly recommend the calibration if you are an M8 shooter and because the M8 is more critical than film, you are the better for it either way
2947863450_94be601856_b.jpg
Click to expand...

Now, that's sharp!
 
My 90mm is in with Don now for calibration to the m8. Re: the body vs lens statement. If my 50mm is spot-on and I calibrate my body to the 90mm wouldn't my 50mm focusing accuracy be off? I am not a camera repair person but it seems from my laymen's view the 50mm would be impacted by messing with the body.
 
If my 50mm is spot-on and I calibrate my body to the 90mm wouldn't my 50mm focusing accuracy be off?
Click to expand...
mountainrivera
To answer your question, if it is an M8, the answer is yes.

If all or most of your lenses are right on, then it should be the lenses that are off that need alignment, not the camera so sending the 90 in was the right choice.

I asked Don if I needed to send the M8 in and the answer was no. The vast majority of the time, it's the lenses
From what he told me, and I find it true, is if you have some lenses that work properly on the M8 and some that don't, it is probably the lens that need adjustment, not the M8. The M8 is more critical of lens error because the sensor is perfectly flat.

I have 6 lenses and sent 3 in to Don. Now all are right on
they should work correctly on a properly adjusted Film "M" camera.

Also, you may get the infinity setting to not quite match perfectly on all of the lenses (goes either past infinity or stops before) in the rangefinder, but focus should be correct.

Again, with my M8, not all of the lenses are dead on in the rangefinder @ infinity, but right on @ Close focus, wide open. A minor problem that is not worth dealing with or worrying about

Hope this helps.
 
" Used on a film camera as a 35mm lens, there would not be an issue at all, but on the M8, it becomes a 50mm and focus is more critical. You loose depth of field more at 50mm and above than 35 and below."
So, I think it will be fine.[/quote]

I have just put my 35mm lens on the M8 to test your hypothesis, and no, its still a 35mm lens, it does not miraculously turn into a 50mm lens. It remains a 35mm lens, and its depth-of-field does not change, irrespective of sensor size. I thought I would just clarify that old chestnut......
 
I have just put my 35mm lens on the M8 to test your hypothesis, and no, its still a 35mm lens, it does not miraculously turn into a 50mm lens. It remains a 35mm lens, and its depth-of-field does not change, irrespective of sensor size. I thought I would just clarify that old chestnut...

Send it in for the upgrade!

Seriously, although the d-o-f remains identical on the image, the smaller image area means 33% more enlargement for the same final image size, so d-o-f is effectively reduced in the final image.

Cheers,

R.
 
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