Sony Carl Zeiss 24mm F2 ZA SSM Distagon T* A-mount lens review by lifeispixels
|lifeispixels#9933 date: Feb-15-2012|
flare control: 5
|ownership:||I own this lens|
|compared to:||Sony 35mm f1.4 G|
|price paid:||1130 USD used, mint|
Quiet and fast SSM motor.
Great range for both full frame and APSC.
Super close MFD.
|negative:||Field Curvature quite pronounced at f2, stop down recommended for subjects in parallel line.|
Focusing from 2mm to infinity is quite hit & miss, it seems a QC problem with some copies so test carefully before you buy.
|comment:||I was looking for a prime lens with wide aperture in this range for photo-journalistic works. First thing that came to my mind was the 35mm f1.4 G. However both used and new ones are uber-expensive and upon testing, the sharpness is disappointing when zoom in, although I like how it renders the image, subject-background distinction, super smooth bokeh, and stylish vignette. However good it was, it's a lens of an old design and its flaws can be very difficult to work when I need to crop images. Not to mention its resale value. Also while 35mm f1.4 G is perfect for full frame camera, it performs worse than the cheap & plastic Sony 35mm f1.8 on APSC. |
For the same budget, I realized that I could buy this Carl Zeiss 24mm f2 SSM and use as wide angle 24mm f2 on A850 and also as a normal prime 36mm f2 equivalent on A77. A great alternative to A850 + 35mm f1.4G for photojournalism.
First impression. The build quality is extremely solid and impressive. Smaller than Sony 16-50mm f2.8 SSM but weighs about the same. The metal focus ring is very nice. Although it's a shame the hood is plastic and looks most vulnerable.
First trying on A77. Focus is smooth, fast and silent, as expected from SSM. Bokeh on APSC is harder to make than on full frame, unless getting closer to subject, otherwise the bokeh quality is smooth and pleasing. However after I tried shooting with A77 for a day, I had the urge to almost return it to the seller. I noticed the focus is quite hit and miss on A77. When the subject is 1-2 meter far or more, even I lock the center focus point carefully, so often the auto focus will go beyond that to infinity and I ended up with images that don't look sharp. I guess that's why some people mention image sharpness issue with this lens.
I came home, google and found a review here that said he needs to adjust -7 micro focus adjustment on his copy. I tested mine and found that my copy needs as much as -8 on both A77 and A850. After that I tried taking pictures in various conditions and different focus ranges with A77, and though the problem is not completely gone, the lens becomes usable on A77. From around 30% hit 70% miss, it's now 90% hit, 10% miss which is acceptable to me giving the extremely small DOF at f2. Focusing on objects closer than 1 meter or macro level is very accurate and never be a problem. It should be noted again that this problem only aggravates on A77. I tried with A850 and it gives 0% miss after adjusting -8. I'm not sure why it misses so much more on A77 than A850. So I seriously need to warn anyone who wants to buy this lens and uses with a camera that doesn't have micro-focus adjustment capability to check carefully the back-front focus issue especially from 2 meter to infinity.
I will need to test more and update here.
The focus issue aside, I'm extremely pleased with the sharpness wild open and stunned when stopped down. Expect corner to corner mind-blowing sharpness on A77, and drop around the edges for full frame. Vignette is non-existent on APSC. And high at f2 on full frame but that can add a style to images. The colors and contrast are amazing. Distortion is extremely low and not necessary to correct in PP. Flare is no issue for me since it's not worse than other lens in the same class. Also one of the things I love most about this lens is how it can get so close to the subject. MFD is only 19cm from sensor. In reality, you can get so close to the subject your lens nearly touch. This is very useful in tight space and when you want to squeeze more bokeh! One thing worth mentioning is the field curvature is quite pronounced at f2, most noticeably when the subjects are in parallel line with the focal plane. For example, taking a group photo of people, the persons in the middle are sharp, the persons around the rule of 1/3 grids are soft, and people at the extreme edge are sharp again. Hence, stopping down recommended for landscape. This problem can be noticeable on a full frame body.
In summary, it's the best wide-normal prime for Sony camera that you can have. See my photos with Carl Zeiss Distagon T* 24f2 SAL24F20Z SSM on my Flickr collection at: http://www.flickr.com/photos/lifeispixels/collections/72157628204412995/
UPDATE: At first I thought this was a normal back-focus issue that can be fixed with micro adjustment. But it is not. All other lens I have, mostly screw drive, can be fixed easily with micro focus adjustment in camera. however for this lens, for an object further than 1-2 meter, -7 to -8 can fix the problem and bring back the focus to its original point however when close focusing, less than 1 meter, it ends up having front focus. If I fix front focusing at macro level, the infinity focus is messed up. I sent the lens to Sony service center and they could only identify the back focus but came up with no solution about irregular focusing behavior throughout the focus range. So I returned the lens to the seller. I will reduce the build rating score to 3 for this. It seems I'm not alone about this problem: http://www.flickr.com/groups/sonycameraclub/discuss/72157627767204993/#comment72157629333633053
UPDATE #2: I got myself a new copy of 24f2 at Sony center and tested fully before paying. The 2nd copy has no focusing problem whatsoever. I recommend trying this lens thoroughly before buying new or 2nd hand.