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Cv 15mm Versus Leica 18mm


tashley

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Fed up with using various 'fixes' for the colour casts of the CV15 on the M9, I yesterday purchased a Leica 3.8 super elmar. I don't like having to do this: I am sure Leica haven't done it on purpose but the truth is that going from an M8.2 to a 9 has resulted in the CV15 no longer being easily useable, thus more or less forcing me to purchase a Leica lens....

 

However, my chagrin is mild. The new lens is great. Really great, and I think one of the better value ones in the current lineup.

 

Here are some interesting comparisons (all right, the shot itself is quite extremely boring!). Whole frame first followed by crops from somewhere near the middle then comparable edge sections. All at ISO160, F5.6, 1/250th, tripod. The net conclusions I draw are that they are both very sharp on centre, both impressive to the edges, but that there is much less vignetting on the Leica and that the colour shifts are much better corrected too. I miss the wider FOV though and will keep the CV as a travel wide, because it is so small and so good.

 

One other thing, and I can't demonstrate this here because I am not at home with my full set of software licences, but I originally opened the files in my copy of C1 and they are much, much better processed therein than in LR. However the copy of C1 I have with me is DB, which means I can't edit or save the files so to prepare them for this comparison I had to use LR. If you look at the second set of images, the glass and wires, you'll see the small diagonal step marks on the slender steel strips. They only occur in LR when I bump up the default sharpening a bit so as to match the look of the C1 files but of course in C1m there's no penalty. Just subtly better detail and micro contrast.

 

Finally, viewed in C1, the Leica lens clearly shows better micro contrast but in the LR processed files presented here that is harder to see.

 

Best

 

Tim

 

 

p726101231.jpg

 

p911940315.jpg

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Can you tell us which manual setting for lens detection you used for the CV15mm? Did you try to use settings for different lenses - perhaps with longer focal length?

 

On my monitor I see a very, very slight red shift on the left edge of the first picture. Is it present on your original?

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tim

thank you for doing this comparison. i'm sure there are a lot of forum members "in the same boat" with favorite lenses exhibiting unwanted color casts.

did you also consider the WATE before choosing the 18mm leica prime? at about €2200 plus finder on the used market, they are not too far away from the leica 18.

cheers

rick

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Can you tell us which manual setting for lens detection you used for the CV15mm? Did you try to use settings for different lenses - perhaps with longer focal length?

 

On my monitor I see a very, very slight red shift on the left edge of the first picture. Is it present on your original?

 

It was as 16mm. I have tried various other focal lengths and they all look weird!

 

The red tinge top left is just the start of it: there are, in those clouds, any number of cyan/blue things going on. It's a mess and it is very much present in the original...

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tim

thank you for doing this comparison. i'm sure there are a lot of forum members "in the same boat" with favorite lenses exhibiting unwanted color casts.

did you also consider the WATE before choosing the 18mm leica prime? at about €2200 plus finder on the used market, they are not too far away from the leica 18.

cheers

rick

 

I did Rick - I used to have a WATE and I'm afraid I think it, and the Frankenfinder, are ungainly. From memory of how it performed, my new 18mm is at least as sharp and shows less distortion and more 'pop' but these things are highly subjective and I'm sure there's an MTF chart somewhere that proves otherwise!

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I did Rick - I used to have a WATE and I'm afraid I think it, and the Frankenfinder, are ungainly. From memory of how it performed, my new 18mm is at least as sharp and shows less distortion and more 'pop' but these things are highly subjective and I'm sure there's an MTF chart somewhere that proves otherwise!

 

the MTFs prove exactly what you say.

peter

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Does this apply to the Leica 18-mm or the CV 15mm?

 

Sorry, I misread you originally: there is indeed a very slight shift in the 18mm shot and I do expect this to be firmwared away in time. The shot with the messy mix of red, blue, cyan and purple is the CV shot.

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I believe Cornerfix will be the way to go for the CV15 on the M9. And, even then, one will need to accept a good amount of luminance vignetting as simply being part of the "look" the lens creates.

 

Cheers,

 

Sean

 

But why this red-drift is always on the left side? (at least much more pronounced). You find it on all CV15/CV12 files and even sometimes on Leica wides up to 28mm. IMO this asymetric behavior must be an issue of the sensor or the in-camera-correction - and maybe fixed someday by firmware-update.

 

Cheers,

 

Dietmar

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When I experimented with the C/V and John Millich's filter holder, I got hard vignetting in the upper corners only! Fed up, I bought a Zeiss 18mm Distagon instead (my excuse: The Leica 18mm I had been clamouring for was still nowhere to be seen) and coded is as a WATE, leaving it always at 18mm as the camera prompted me. Worked beautifully. I am now eagerly waiting for my M9 so I can test-fly the rig. If it works as well on the M9 as it does on the M8, I will keep it.

 

The old man from the Age of the Hologon

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But why this red-drift is always on the left side? (at least much more pronounced). You find it on all CV15/CV12 files and even sometimes on Leica wides up to 28mm. IMO this must be an issue of the sensor or the in-camera-correction - and maybe fixed someday by firmware-update.

 

Cheers,

 

Dietmar

 

Hi Dietmar and Tim

I was testing the Zeiss 25 today, and that also showed a very slight red drift (less than your 18 I think Tim) but like Tim's result here - it was on the left hand side.

 

Very strange.

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But why this red-drift is always on the left side? (at least much more pronounced). You find it on all CV15/CV12 files and even sometimes on Leica wides up to 28mm. IMO this asymetric behavior must be an issue of the sensor or the in-camera-correction - and maybe fixed someday by firmware-update.

 

Cheers,

 

Dietmar

 

I don't know. I don't have enough data to know how common that behavior is. When I see side to side variations in my own vignetting/cyan drift tests I always allow for the fact that no two quartz lights can be identical,etc.

 

In other words, to really test that (and eliminate the possible confounding variables) one would need lab quality lighting and materials.

 

So, again, I don't know to what extent this is happening and, if it is indeed a pattern, I don't know why.

 

Sandy? Have you seen this at all?

 

Cheers,

 

Sean

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Sean,

 

Yes, I am seeing quite a few images with odd asymmetrical vignetting. That did happen very slightly on the M8, but what's strange here is that with the M9 it seems to be mainly over-correction on the left hand side, and is a lot more visible.

 

Also, there's evidence that vignetting on the M9 may be a lot more sensitive to color temperature of the light than the M8. The M8 corrections could be thrown by exotic light sources e.g., some types of fluorescent light, but the M9 seems to vary visibly even between overcast and direct sun on the CVs.

 

But I also have too little data to form a firm conclusion. Anyone out there with an M9 and the ability to do some test shots of a well lit wall under a variety of different conditions, PM me!!!!

 

Regards,

 

Sandy

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Guest EarlBurrellPhoto
I believe Cornerfix will be the way to go for the CV15 on the M9. And, even then, one will need to accept a good amount of luminance vignetting as simply being part of the "look" the lens creates.

 

Cheers,

 

Sean

 

That's such a shame because on film that lens has remarkably little falloff considering the modest cost of the lens. We can only hope that as technology improves, future 24x36-sensor digital Leicas will be able to at least replicate the same level of falloff in the corners as there was on film.

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Sean,

 

Yes, I am seeing quite a few images with odd asymmetrical vignetting. That did happen very slightly on the M8, but what's strange here is that with the M9 it seems to be mainly over-correction on the left hand side, and is a lot more visible.

 

Also, there's evidence that vignetting on the M9 may be a lot more sensitive to color temperature of the light than the M8. The M8 corrections could be thrown by exotic light sources e.g., some types of fluorescent light, but the M9 seems to vary visibly even between overcast and direct sun on the CVs.

 

But I also have too little data to form a firm conclusion. Anyone out there with an M9 and the ability to do some test shots of a well lit wall under a variety of different conditions, PM me!!!!

 

Regards,

 

Sandy

 

If we get good examples of this (white wall, controlled lighting, etc.) then I will bring that to the Leica engineers. I can't do that testing myself right now because I have other review work to finish but if we gather the examples I will get them to the right engineers.

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That's such a shame because on film that lens has remarkably little falloff considering the modest cost of the lens. We can only hope that as technology improves, future 24x36-sensor digital Leicas will be able to at least replicate the same level of falloff in the corners as there was on film.

 

I haven't tested it on film but I've been told there's quite a bit of luminance vignetting. Are you sure you haven't seen that?

 

Cheers,

 

Sean

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In other words, to really test that (and eliminate the possible confounding variables) one would need lab quality lighting and materials.

 

 

Or simply by turning the camera for 180 degrees - and you will find the red-drift again on the left side (camerawise); but now on the right side of the scene.

 

Cheers,

 

Dietmar

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