Article Index

 

Flare

This lens flares, but than again, every lens flares. There is no hiding from it in this lens - you get flare at all apertures and all focal ranges if you're not careful enough. Samples below show what you would get with the sun positioned right near the corner of the frame - probably the worst possible option for any lens, not just Carl Zariss Vario-Sonnar 24-70/2.8. In these situations you would get ghosting, low contrast, blown out highlights, color shifts, basically you name the artifact and it will be there. Hood helps a bit, but does not block all stray light in the worst possible case and you still end up with flare. Just don't point the lens directly into the sun and you should be fine. 

 

24mm

thumb-flare1-cz-vs-24-70mm-f28za-iso100-s1250-f28-24mm thumb-flare2-cz-variosonnar-24-70mm-f28za-iso100-s160-f8-24mm

70mm

thumb-lflare1-cz-variosonnar-24-70mm-f28za-iso100-s640-f28-70mm thumb-lflare2-cz-variosonnar-24-70mm-f28za-iso100-s100-f8-70mm

Vignetting

Carl Zeiss Vario-Sonnar 24-70mm f/2.8 ZA shows variable levels of light falloff across the zoom range. As one would expect, vignetting is higher at wider apertures and is worst at 24mm, where it reached ~2.3EV at f/2.8. At ~1.6EV, vignetting is still fairly high even when you stop down the aperture to f/4. Beyond that vignetting gets more or less manageable. 35mm is a bit of transitional point with Imatest registering ~1.3EV of light falloff at f/2.8 and ~1EV at f/4. Longer focal ranges also show vignetting at wide apertures, but not as pronounced.

Sony a850 (24Mp)

a850-vig-cz-variosonnar-24-70mm-f28za

 

From practitioners' perspective, vignetting would actually be quite visible at 24mm, which can reduce overall quality of image (in the periphery) if not taken care of either within the camera or during post-processing. If you're using Adobe Photoshop, try setting Vignetting correction to +20/+25 for 24mm/f.28 and +15/+18 for 24mm/f/4. 35mm is a bit better, but you might still want to get rid of vignetting here as well - try +10/+12 for 24mm/f.28 and +5/+8 for 35mm/f4. 50mm-70mm should not be a problem for you and should not require meddling with vignetting

 

Vignetting @ 24mm

lvig-a850-24mm-cz-variosonnar-24-70mm-f28za

Vignetting @ 35mm

lvig-a850-35mm-cz-variosonnar-24-70mm-f28za

Vignetting @ 50mm

lvig-a850-50mm-cz-variosonnar-24-70mm-f28za

Vignetting @ 70mm

lvig-a850-70mm-cz-variosonnar-24-70mm-f28za

 

 

Distortion

As hinted on earlier, distortion is the major Achilles heel of Carl Zeiss Vario Sonnar T* 24-70mm f/2.8 ZA lens. Most notably at 24mm, where barrel distortion reaches ~2.8%, which would be noticeably in real life. While it is possible to correct distortion during post-processing, the image does not recover quite completely and the residual artifacts of the correction would still persist. Post 35mm, distortion is much more manageable, even mild I'd say - at 35mm we still see barrel distortion of ~1.1%, at 50mm barrel distortion almost disappears, clocking a mere ~0.5% and at 70mm barrel distortion turns into slight pincushion distortion of ~0.4%.

24mm

dist-a850-24mm--28

35mm

dist-a850-35mm--12

50mm

dist-a850-50mm--06

70mm

dist-a850-70mm-+05