15mm Heliar vignetting: R-D1 vs. R4A

[squirrel$$$bandit]

Am I losing my mind, or does the CV 15mm Heliar vignette more on the R-D1 than it does on a film camera? I bought the lens for the R-D1 and just recently shot my first roll on film with it. Even at wide apertures, vignetting seems to be minimal--and yet it vignettes on the R-D1.

Why would this be?

 

[LCT]

...Why would this be?

Because the R-D1 does vignette as well, more so than any film camera. For an general explanation see the link below.
http://www.l-camera-forum.com/leica...240-new-sensor-going-arrive-4.html#post654234

 

[cam]

the SA 21mm does the same thing (as did a CV i borrowed). not all shots, mind you, but extremes. you are not losing your mind.

i've found if you put the proper focal length (under Special) in whilst using Epson Raw it helps, even when it's set at 0.

 

[squirrel$$$bandit]

Because the R-D1 does vignette as well, more so than any film camera. For an general explanation see the link below.
http://www.l-camera-forum.com/leica...240-new-sensor-going-arrive-4.html#post654234

Aha, thank you! From that post:

compared to film, digital sensors are much more sensitive to the direction in which light impinges on it. Off axis, the paths of the photons have to be drastically and precisely bent in order to make them fall down the CCD wells and register...Microlens technology cannot bend light through 45°, and may never be able to do it.

That makes sense--I never though about how the microlenses would react to slanted light.

I don't use Photo Raw, just Adobe Lightroom, and it does indeed have a very effective vignetting control. I can get pretty good results if I want the vignetting to go away, but often I like it the way it is.

I guess that this explains why aperture doesn't matter either. In fact, unlike on a film camera, it should be WORSE at small apertures, because more of the light would be coming in at a steep angle, correct? The 15mm Heliar's modest natural vignetting at wide apertures would be invisible on the R-D1 because of the crop--rather, it's the sensor's own tendency to vignette that I'm looking at.

 

[LCT]

...I guess that this explains why aperture doesn't matter either. In fact, unlike on a film camera, it should be WORSE at small apertures, because more of the light would be coming in at a steep angle, correct?...

Light fall-off is generally maximum at full aperture and decreases more or less when stopping down.
Same with film but vignetting is generally more pronounced with the R-D1.
Never used the Heliar 15mm so far but it must vignette around one stop with film at full aperture if i remember well and i would be surprised if it were better on the R-D1.
See what Sean Reid wrote about it:
"vignetting is significant even when this lens is stopped down. With more common and less uniform subjects the vignetting is less noticeable but still quite obvious. To use this lens on the R-D1, a photographer would need to either accept moderate vignetting as part of the look of the picture or manually remove it in PhotoRAW, especially with pictures made at larger apertures. The vignetting from this lens is noticeable enough, with common subjects, that many photographers will likely want to correct it. The lens vignettes more strongly than the 12/5.6."
http://www.luminous-landscape.com/reviews/lenses/rd-1-lens.shtml

 

[squirrel$$$bandit]

Light fall-off is generally maximum at full aperture and decreases more or less when stopping down.
Same with film but vignetting is generally more pronounced with the R-D1.

Well, i just tested it...wide open there is LESS vignetting on the R-D1, as I suspected would be the case! The vignetting in this case isn't coming from the lens itself, but by the angle of light to the sensor, as LCT pointed out. Surprising result!

 

[sabrewolf]

Yes, to get less vignetting on RD-1, use the widest aperture possible

 

[squirrel$$$bandit]

It still doesn't quite make sense in my mind, but it works...