Photo Jottings

Many people are wondering how the Sony Carl Zeiss 24mm F/2 prime lens performs when compared directly to the Sony Carl Zeiss zooms at 24mm.  Below is a direct comparison, but you should not use the outcome here solely when making a purchasing decision.  There are other factors that are sometimes far more important than sharpness or distortion.  Heft, flare/ghosting control, focusing speeds and fast apertures are all very important too, it all depends on what works best for the photographer.

 

This comparison review will involve the Sony Carl Zeiss 24mm F/2 SSM, Sony Carl Zeiss 16-35mm SSM and Sony Carl Zeiss 24-70mm F/2.8 SSM using the A900 full frame camera, and the Sony Carl Zeiss 16-80mm F/3.5-4.5using the Sony A580.   The APS-C combination I threw in just for fun.  Also, we’ll start off at F/2.8 (F/4 with the APS-C lens) to avoid a bunch of blank spaces since the other three lenses do not have F/2.

Distortion comps

Sony Carl Zeiss 24mm, minor to moderate barrel distortion.

Sony Carl Zeiss 16-35mm at 24mm, almost flat

Sony Carl Zeiss 24-70mm @24mm, moderate to heavy barrel distortion.

Sony Carl Zeiss 16-80mm @16mm, with Sony A580, moderate to heavy barrel distortion

Distortion is flattest with the CZ 16-35mm zoom, mostly because the 24mm length comes in the middle of the zoom.  I see moderate levels of barrel distortion with the 24-70mm, and (APS-C only) 16-80mm, both have similar, slightly wave-type distortion signatures that don’t straighten completely with standard distortion correction tools.  The CZ 24mm prime has minimal distortion, and needs little or no post processing adjustments, unless straight lines are near edges of the image.

Below are crops taken from the centers of the images.  White balance was manually set to 5400k, manual focusing used, and bracketed to the best possible sharpness tested at both wide open and F/5.6 to guard against focus shift inaccuracies.  The house front is approximately 400′ (122m) away.  Additionally, the house is not crooked, my eyes are, sorry.  You’ll notice the leveling device on the A580 (CZ 16-80mm crops) works good, to bad the A900 doesn’t have it!

The Sony CZ 24mm image crops are exactly the same as I used in the full frame section of the review.  The image crops from the other lenses were taken at the same time.

 

I don’t see much, if any sharpness differences in the crops above, at any aperture.  It looks like the CZ 16-80mm has a little less contrast than the more expensive full frame lenses.  Don’t judge the CZ 16-80mm by the color, I left the default color settings alone, and that seems a little dull, and no, it wasn’t shot in adobe RGB.  Of course the CZ 16-80mm crops are not as detailed, but they come from a 16mp APS-C sensor, instead of the 24mp full frame sensor of the A900.

 

Mid sections below

 

The mid-sections show a far different story.  The CZ 24mm is soft unless stopped down hard.  the two zooms are quite sharp, even wide open.  Actually, the CZ 16-80mm crops are probably just as detailed as the CZ 24mm if you upsized them to match the other crop areas, that’s just plain crazy!

 

Corners next

 

The corners look very similar to each other, that is, they’re soft at large apertures, but sharpen up pretty well at F/8-11.  Color fringing is strong on the CZ 16-80mm, much more so than the other lenses.

 

To sum up the results; the centers look similar in all the zooms, although let’s not forget the CZ 24mm is a stop wider at F/2, which I didn’t show.  If you do a lot of hand-held, low light shooting, it offers a very useful, and important full stop of light.  The mid-sections are really soft at wide apertures with the CZ 24mm; that’s the result of strong field curvature, and the only fix is stopping down the aperture.  Thankfully, the zooms don’t have that problem.  The corners are about the same on all the lenses, at all apertures.  Contrast seems about the same on all the lenses, bar the just-for-fun CZ 16-80mm, which seems a little flat when compared to the other lenses that cost much, much more.

 

Is my copy of the Sony Carl Zeiss 24mm F/2 good, or would it flunk quality control?  Based on the fact that the lens is very sharp in the centers wide open, and other areas sharpen up by F/8 or so, I have to believe my sample is good.  I only tested one copy of the other lenses, and have never had a bad Sony lens, their quality control is pretty good.  However, there could be sample variations, but until I somehow get another copy to test, the results above will stand.

 

Here is the full reference image for the center crops, the other crops come from repositioning the subject in the frame accordingly.

 

Sony Carl Zeiss 24mm F/2, @F/8