Lens or body

[poppers]

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Good Morning. I've had my M6 about 8 years and used it with a Zeiss 35mm F2 Biogon. I was very happy with the results and  constantly amazed at the sharpness and colour of the  rendition of the lens. In the back of my mind i always had a niggle about the summicron 35 asph and though from reading reviews knew they weren't miles apart still felt i had to scratch the itch so to speak. 

About 10 months ago I bought a mint 35 Asph summicron  and was eager to try it.  Now foolishly the first few rolls i shot, instead of sending them away to my usual lab i developed them somewhere else so added another change into the equation. 

I was slightly disappointed at the results. I didn't expect night and day difference but the summicron seemed to be lacking something.  The colour was quite different which i expected but the sharpness seemed to be lacking or slightly off. 

In portraits for instance when first looking at prints they seem OK then a closer look reveals that the lens seems slightly sharper away from the centre or slightly in front or behind where i thought i had focussed. For example the fibres in wool on the shoulders of a person being sharper than their face. 

 My rangefinder is ever so slightly out and wonder if this could be the issue but would have thought any slight miss focus would be over come when stopping down.  I'm a film shooter so have no other way of testing the lens in real time. 

I'm going to go  back to the dealer before the guarantee runs out and have them take a look at it. Some of me thinks i liked and was used to the Zeiss so much that it's the change that unsettles me and there is nothing wrong with the lens. Then i see other peoples photos even on film and they do seem sharper. 

 

regards

 

Edited January 26, 2019 by poppers
typos

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[pgk]

13 minutes ago, poppers said:

In portraits for instance when first looking at prints they seem OK then a closer look reveals that the lens seems slightly sharper away from the centre or slightly in front or behind the lens. For example the fibres in wool on the shoulders of a person being sharper than their face.

If the rangefinder on the camera is out then the point of focus should be consistently wrong. If the focus shift is variable as you describe, then the lens needs looking at because this should not be so and there is something amiss with the lens. In the first instance see if you can visit your dealer and try the lens on a digital body to see if the variation is consistent or not, and check that you are getting planar focus (ie there is no inconsistency across the frame). The problem is that we often try to find simple solutions for problems which might have several causes. So you may have a de-centred lens (sharper on one side than the other and which is out of calibration (plane of focus not where it should be). The two could interact and the result might well be unevenness in sharpness which appears variable. Either way it can be corrected by Leica.

[poppers]

Thanks for your response. Would you think  the effect would be more pronounced and easier to spot in a digital body if it’s the lens ? 

[Jon Warwick]

Tough to answer about causes of this issue given the variants you discuss.

But if you attach the lens to (say) an M10 in the dealership and take some images as tests, you should get an idea if it’s the lens when you scroll in 100%. The screen on the back of the M10 is high Rez enough to give you a clear idea of what’s sharp or not.

 

[Gregm61]

Digital bodies will definitely “expose”, or magnify any lens issues as there’s no grain to mask any slight issues/aberrations.

Of course, the mechanical rangefinder is subject to the same calibration issues and if it’s a body like my M262 with no EVF option of viewing/focusing you don’t have the option of precise focus testing, although you will see the resulting image at once and will not have to wait for a developed film roll to see the results.

Edited January 26, 2019 by Gregm61

[pgk]

1 hour ago, poppers said:

Thanks for your response. Would you think  the effect would be more pronounced and easier to spot in a digital body if it’s the lens ? 

Well my reasoning is that its a lot quicker to check using a digital body than film! And it will either show up a consistent problem (single lens issue or camera) or inconsistent (lens issues).

[spydrxx]

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Since you mention your RF is slightly out of alignment, there is a way you can check focus, and I've done it with lots of RF bodies over the years. You mount your body on a tripod and measure the distance to an object from the film plane, as a point of reference. Open the back of the camera and hold it open with a rubber band. Place a piece of fine ground glass (or a focusing screen from a SLR on the film rails, open the shutter with a cable release and using the rangefinder focus the image. Now observe the actual image on the ground glass with a loupe or 50mm lens to magnify it. If key elements you focused on with the RF are sharp, all is good, if not, your rf needs adjustment. As an aside, just check what your focusing scale on the lens says....does it match your actual measured distance?

[poppers]

43 minutes ago, spydrxx said:

Since you mention your RF is slightly out of alignment, there is a way you can check focus, and I've done it with lots of RF bodies over the years. You mount your body on a tripod and measure the distance to an object from the film plane, as a point of reference. Open the back of the camera and hold it open with a rubber band. Place a piece of fine ground glass (or a focusing screen from a SLR on the film rails, open the shutter with a cable release and using the rangefinder focus the image. Now observe the actual image on the ground glass with a loupe or 50mm lens to magnify it. If key elements you focused on with the RF are sharp, all is good, if not, your rf needs adjustment. As an aside, just check what your focusing scale on the lens says....does it match your actual measured distance?

Perhaps I could give this a try. It seems to be out vertically by a small margin. I can never get the rangefinder image image to totally be clear.  The thing is I did  not notice any adverse results before with the Zeiss. What I should have done I guess is take the same image just changing lenses in between  each shot   

 

[analog-digital]

vor 6 Stunden schrieb poppers:

.....Now foolishly the first few rolls i shot, instead of sending them away to my usual lab i developed them somewhere else so added another change into the equation....

That could be the problem. Do it again with your usual lab.....

[poppers]

I did and I was still unsatisfied with the results. 

[poppers]

1 hour ago, poppers said:

I did and I was still unsatisfied with the results. 

That wasn’t meant to sound harsh. I appreciate your input Analog-digital. 

[farnz]

My apologies if this sounds a bit like a lecture (not my intention at all) but I think it's important to understand the factors at play here.

There has long been a difference between Leica and Zeiss lenses in that they render pictures in different ways and many people interpret this as difference in this nebulous term "sharpness", which really has no technical meaning.  What is commonly termed "sharpness" is a combination of acutance and resolution.  Acutance is the contrast along an edge in a picture and resolution is the ability to resolve fine detail.  

So, with high acutance edges will be clearly defined and with low resolution captured detail and micro-contrast will be lower so the transition from black to white will be stark.

On the other hand, high resolution will provide gentler transitions (gradients) from black to white and low acutance will give less stark edges.  

Both of these will provide "sharp" images but in different ways.

Zeiss lenses typically have higher acutance and lower resolution so features are very clearly defined, which some interpret as sharpness.  However, Leica lenses have traditionally had higher resolution and lower acutance because Leica's priority is high resolution.

What you might be interpreting as 'less sharp' images from your Summicron compared to your Biogon might simply be the way the Summicron renders the image.  High acutance works well with pictures that contain a high proliferation of edges but high resolution works well with pictures with a high proliferation of gradual tonal transitions.  As an analogy, this could loosely be translated as acutance for cityscapes and resolution for pastoral pictures (although I will quickly add that both Zeiss and Leica will do very well with either but will produce slightly different pictures).  Add to this that Zeiss lenses have traditionally offered more saturated and warmer colours than Leica lenses, which are designed to replicate natural colours as closely as possible and this might go some way to explaining the difference you're seeing between pictures from the two lenses.

Pete.

 

[darylgo]

Wow, how can I follow Pete's post, bravo.    The Zeiss Biogon is an exceptional lens, I've attempted what you are and kept my Zeiss as the only 35mm and only Zeiss I own.  

Edited January 27, 2019 by darylgo

[tobey bilek]

Get some matt acetate  and cut a strip like film.  Open or remove back,  tape strip where film goes,  and you will see image like ground glass focusing if you open the shutter on B with locking cable release.

 

Use a coat or black cloth as if it were a view camera dark cloth.   

Edited January 27, 2019 by tobey bilek

[250swb]

4 hours ago, darylgo said:

Wow, how can I follow Pete's post, bravo.    The Zeiss Biogon is an exceptional lens, I've attempted what you are and kept my Zeiss as the only 35mm and only Zeiss I own.  

Well you could consider what the OP said and follow it by asking 'what has all this to do with detail being sharper in front of or behind where the OP thought he'd focused'.

Rendering and acutance can't alter the actual focus point, that would be the rangefinder, a fault in the lens, or inherent focus shift in the lens.

[darylgo]

7 hours ago, 250swb said:

Well you could consider what the OP said and follow it by asking 'what has all this to do with detail being sharper in front of or behind where the OP thought he'd focused'.

Rendering and acutance can't alter the actual focus point, that would be the rangefinder, a fault in the lens, or inherent focus shift in the lens.

No doubt, this could have been restated if it hadn't been addressed in the first response (post #2) by Paul about the focus shift, decentering etc. and later responses about faulty lens, rangefinder.    Btw- the Biogon is a very planar lens except for edges when stopped down where it starts showing slight field curvature at the edges and only getting significant in the very corners.  

 

[poppers]

I've done a few focusing experiments. The rangefinder seems ok at infinity or at least its harder to tell if it's off, but when focusing closer it doesn't appear perfect. I focused on one of my guitars upright in a stand. When focusing i brought all strings into alignment running from top to bottom. When these are in focus the frets which run from left to right are slightly out and the fret marker dots don't line up either. You can definitely see two frets as opposed to one. i'm not sure  if this is enough to be the cause of my focusing concerns. 

[jdlaing]

What aperture setting?

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[farnz]

You could try placing your camera at an angle to the fret board with the guitar horizontal and focussing on one of the central strings with the aperture wide open.  If one of the other strings turns out to be in focus then you'll be able to confirm whether it's front or back focussing and roughly by how much.

Pete.

[poppers]

9 minutes ago, jdlaing said:

What aperture setting?

I’m just using the rangefinder not taking any shots.