Sony 24-70mm F/2.8 SSM Carl Zeiss Review - Photo Jottings

Sony 24-70mm F/2.8 SSM Carl Zeiss Review

Here’s a brief look at the Sony 24-70mm F/2.8 SSM Carl Zeiss zoom lens.  Scroll down for the main review.

Lens
SAL2470Z  Sony 24-70mm F/2.8 Carl Zeiss Vario-Sonnar ZA
Box contents
Front and rear caps, hood, softcase and users manual.
Cost
$1998 retail
Build quality
Very good
Additional information
Also consider the Minolta AF 28-70mm F/2.8 G orSony/Tamron 28-75mm F/2.8 for much less money.
Specifications below
Optical configuration
17 elements in 13 groups
Angle of view
84°-34° full frame, 56°-23° APS-C.
Aperture
9 blades, circular
Full frame and APS-C
Yes, full frame and APS-C.   APS-C equivalent, 36-105mm
Depth of field and focus scales?
Distance window.
Minimum focus, image plane to subject
12.7″ (323mm)
Minimum focus, end of lens barrel to subject
5.35″  (136mm)
Hard stop at infinity focus?
No
Length changes when focusing?
No
Focus ring turns in AF?
No
Filter size
77mm
Filter ring rotates?
No
Distance encoder?
Yes
Max magnification
0.25x
Min. F/stop
F/22
Sony teleconverter compatible?
No
Length changes when zooming?
Yes
Dimensions WxL  (my measurements)
3.3″ x 4.3″   83mm x 110mm
Maximum  extended length (my measurements)
5.6″  (142mm)
Weight bare (my scale)
33.9oz  (961g)  35.2oz (997g) with caps
Requisite product shots.

october08/s2470kit.jpg
Contents of box.
october08/s2470sd.jpg
Side shot drawn in.
october08/s2470sdex.jpg
Zoomed out to 70mm.
october08/s2470bk.jpg
Backside.
october08/s2470ft.jpg
Front element
2012/cz2470mtf2.jpg
Sony X-ray view and MTF chart
The Sony A700 and Sony A900 were used for this review.  For full frame results, go to the bottom of the page.  For a better understanding of my review methods and terminology, go here.
See the comparison review were the Tamron 28-75mm F/2.8 out performed this lens in sharpness, for about a third of the price.
The (made in Japan) Sony 24-70mm F/2.8 Carl Zeiss is a professional grade lens (large, heavy and expensive) meant for people on the street, such as news photographers and Paparazzi.  Amateurs with loads of cash will buy this lens to look cool while on vacation.  People who use a camera all day for work will buy this lens because it can stand up to continuous hard use, has instant auto-focus override, and can perform well in dim lighting.  So how well does it perform?  Read on!
This wide to medium range zoom is large and heavy compared to other lenses covering this length.  It has a constant fast aperture of F/2.8 with an extending zoom, (see images above), unlike the internal zoom mechanism of the Minolta AF 28-70mm F/2.8 G, of which I’ll be making comparisons to throughout the review.  The color and texture of the Sony Carl Zeiss lenses are slightly different than the Sony lenses and camera bodies, they have a duller, rougher type finish.  You’ll never notice this unless you examine them side-by-side.  The lens also has the standard Sony rubber ribbed grip areas that hold way too much dirt, and is hard to clean off, but that’s life with Sony lenses.  There’s a focus distance window along with a single focus hold button, which can be changed to DOF on select camera bodies, this button also serves as a MF/AF switch, see image above.  The EXIF data matches up with the focal length marks, which come at 24mm, 35mm, 50mm, and 70mm.  Increments are 5mm apart (after 30mm) in the data, but 65mm is missing, that’s the way it is.  The lens is multi-coated with the magenta/green look typical for Sony lenses.  Sony claims the use of two aspherical, and two “ED” glass elements in the construction of the lens.  Don’t forget the T* (star) coating!!
Build quality is very good.  It looks like it has some ABS around the barrel, and a metal barrel extension tube.  The zoom is a little stiff in my opinion, but my copy has had very little use, so it may free up some in the future.  No worries about zoom creep, which is good, as there is no zoom lock.
Auto-focusing is very fast, accurate and silent.  Manual focusing takes just over 1/4 turn from Close-in to infinity, with no back slop.  All the Sony SSM units (so far) have an over-drive manual focusing system, that is, if you turn the focusing ring a certain amount, the distance numbers in the window will turn a lesser amount.  This allows more precise manual focusing.
Lens flare/ghosting.  Fair.  Check out the samples below.  If the sun is near the image, you’ll need to block it with your hand, If the sun is in the image, you’ll see some heavy ghosting.  Pointing it directly at the sun looks ok, and much better than the Minolta AF 28-70mm F/2.8 G lens. If you like taking pictures with the sun in the image, use the Sony 18-70mm kit lens, which has the best control of flare and ghosting of any zoom I’ve tested.
Color fringing.  Very good control, and among the best of all the fast mid-zooms I’ve tested.  I see a tiny amount in extreme conditions, see the 70mm center crops.  I see little to no color fringing along the sides.
Bokeh.  Good.  It looks smooth at F/2.8, wide angle, then nearly as good at 70mm.  I think the bokeh on this lens is the best out of all the mid-zooms I’ve tested, such as the Minolta AF 28-70mm F/2.8 G, and the Konica Minolta AF 28-75mm F/2.8.
Color.  Similar to other Sony lenses.
Coma.  None on an APS-C camera.
Close-up filter.  N/A.
Filter size is 77mm. This size is becoming more popular every year for Sony.  They also use it on the 16-35mm F/2.8, 70-400mm G, 70-200mm F/2.8 G, CZ 135mm F/1.8, and the DT 11-18mm F/4.5-5.6.
Normal filters cause very slight corner darkening on full frame results, F/2.8 @ 24mm, but none on APS-C cameras.
Distortion.  See below.  Mild to moderate barrel distortion at 24mm.  Distortion is flat at 30mm-40mm, then it turns to mild/moderate pincushion.  Fairly good control here.
Distortion examples
october08/s2470disbrl.jpg
24mm, mild to moderate barrel distortion.
october08/s2470dispin.jpg
Mild to moderate pincushion at 70mm.

 

Random samples

 

Sony 24-70mm CZ, 24mm F/5.6
Minolta 28-70mm G, 28mm F/5.6
october08/2470ssun2.jpg
october08/2870msun2.jpg
Sony 24-70mm CZ, 24mm F/5.6
Minolta 28-70mm G, 28mm F/5.6
october08/2470ssun.jpg
october08/2870msun.jpg
Bokeh,  24mm F/2.8
Bokeh,  24mm F/4
october08/2470bok2428.jpg
october08/2470bok2440.jpg
Bokeh,  70mm F/2.8
Bokeh,  70mm F/4
october08/2470bok7028.jpg
october08/2470bok7040.jpg
Full image extreme samples of flare/ghosting above.  Only fair control at all focal lengths.   You’ll notice in the comparisons that the Minolta has slightly more ghosts with an offset sun shot, and a huge ring around a centered sun.  The Sony performs better with the sun in the image.  But that doesn’t mean you can wave this baby around close to the sun.  This lens will haze hard when the sun is close to the image periphery, (which is typical of these kind of lenses) you’ll need to use your hand to block any bright lights from hitting the front element, the hood just doesn’t do the job.  Also, don’t lose the hood that came with this lens, as it will set you back $130 for a new one–Sony massive profit generator!!  Bokeh examples above, pretty smooth at F/2.8 across the zoom, and not bad stopped down.  Samples where taken from the central background area of the image, about 8ft (2.3m) behind the subject, and cropped at 100%.
Light fall-off.
Light fall-off or corner shading is non-existent at F/2.8 from 24mm to 70mm.  No problems on a cropped sensor camera, but see full frame results at the bottom of the page.

           24mm F/2.8
             24mm F/4
october08/2470vig2428.jpg
october08/2470vig2440b.jpg
           70mm F/2.8
             70mm F/4
october08/2470vig7028.jpg
october08/2470vig7040.jpg
Center and corner sharpness.

Below are crops from the image centers at 24mm.

              24mm F/2.8
           24mm F/4
october08/2470ctr2428.jpg
october08/2470ctr2440.jpg

 

Now the 24mm corner crops.

 

           24mm F/2.8
             24mm F/4
october08/2470cn2428.jpg
october08/2470cn2440.jpg
The 24mm center crops show very little improvement by stopping down, that’s good.  There’s a hint of contrast loss from spherical aberration at F/2.8, but the image is still sharp.  At F/4 everything looks great.  The 24mm corners look as good wide open as stopped down, again, very good.
Below, look at the 70mm centers.
           70mm F/2.8
              70mm F/4
october08/2470ctr7028.jpg
october08/2470ctr7040.jpg

 

70mm corners below.

 

           70mm F/2.8
              70mm F/4
october08/2470cn7028.jpg
october08/2470cn7040.jpg
On to the 70mm centers, where the results are pretty much the same as the wide angle shots, pretty sharp at F/2.8, then maybe a hair sharper one stop down, but only visible blown way up on a computer screen.  I see a tiny bit of contrast loss at F/2.8, and some axial color fringing which goes away at F/5.6, funny how it’s not there at F/2.8.  It’s very minor and not something that is visible unless viewed at large sizes as I said above.  Keep in mind the full images would print out 45″ (1.14m) long as they appear in the crops using an A700.  The corners really aren’t helped too much by closing the aperture.  Obviously, the corners aren’t as sharp as the centers, but they still look good.  Most of the image is nice and sharp with an APS-C camera no matter what the focal length or aperture.  Ironically, this lens performs much the same as the completely different designed Minolta AF 28-70mm F/2.8 G.
Let’s check out the macro capabilities of this lens.

Below, check out the sample and click (347kb) for a 100% cropped portion of the full image.  The sample shot was taken with the Sony A 700 12.2MP camera.  The subject is a standard US stamp, 1″x 3/4″ or 25.4mm x 19mm.  Also, note the macro shot was taken as close to the subject as focusing allowed; in this case a rather short 5.35″ (136mm), measured from the front of the lens barrel to the subject.
As close as you can get, F/4.
The Sony 24-70mm F/2.8 CZ has a rather large reproduction ratio of 0.25x, and turned in a great close focus shot, taken at F/4, it doesn’t get any sharper by stopping down.  F/2.8 looks soft with test charts, but looks fine in real pictures.

Full frame results using the Sony A900 below.

 

Check out the differences when using a film or full frame camera below.  I’m only pointing out the noticeable issues as compared to the APS-C bodies, so if I don’t show it here, the results are not significantly different enough to warrant posting an additional set of images in this section.

 

Light fall-off

 

         24mm F/2.8
          24mm F/4
october08/2470ffvig2428.jpg october08/2470ffvig2440.jpg
         24mm F/5.6
          24mm F/8
october08/2470ffvig2456.jpg
october08/2470ffvig2480.jpg
         70mm F/2.8
          70mm F/4
october08/2470ffvig7028.jpg
october08/2470ffvig7040.jpg

 

Light fall-off is somewhat heavy at 24mm, F/2.8, but it isn’t all that noticeable in real shots, see image below.  Stopping down gets rid of most, but not all dark corners.  Also, when using a regular filter, (not thin) the corners are slightly darker wide open at 24mm.  At 70mm, there’s mild corner darkening with a very smooth transition, which is not noticeable in real shots.

 

Full image from A900 below.

 

october08/2470ffvig.jpg

 

Here’s another variation of the all-too-typical backyard scene.  This time we see the results of the lens set to 24mm and F/2.8.  As you can see, the light fall-off is not too bad in real life, and as I always say, don’t shoot broad daylight scenes using F/2.8!

 

24mm corner samples next.

 

         F/2.8
          F/4
october08/2470ffcn24f28.jpg october08/2470ffcn24f4.jpg
         F/5.6
          F/8
october08/2470ffcn24f56.jpg
october08/2470ffcn24f8.jpg

 

The corners are softer than the APS-C crops show.  This is normal, and the crops look good a couple of stops down.  These were taken from the extreme corners, so don’t worry about this as it might be covered by a picture frame.  Does anyone still print their pictures out and put ’em on the wall nowadays?

 

70mm corners below.

 

         F/2.8
          F/4
october08/2470ffcn70f28.jpg october08/2470ffcn70f4.jpg

 

The 70mm corners don’t change much, you mostly see the elimination of light fall-off.  Things sharpen up a little as you stop down, but not much, and there isn’t much difference between the images above, and the APS-C shots.  Obviously, the corners aren’t as sharp as the centers, but for full frame, extreme corner shots, they still look good.

 

Distortion next.

 

october08/2870dis900.jpg
Barrel distortion @ 24mm on A900
october08/2870disp900.jpg
Pincushion distortion @ 70mm on A900

 

There is moderate distortion at both ends on the A900, but not enough to be noticeable unless you’re shooting horizons or buildings.  The barrel distortion pattern is complex, showing a rise in the middle, then falling off hard towards the sides, and leaving the ends flat.  This requires extra effort to correct in post-processing.  Pincushion is a gradual curve, and is easy to fix.

 

Coma results with full frame.

 

F/2.8
F/4
october08/2470bokff28.jpg october08/2470bokff40.jpg

 

This is coma @ 24mm on the A900.  It’s controlled well, a little better than the Minolta AF 28-70mm F/2.8 G lens.  Don’t try to compare crops between lens reviews as I have taken them on a different day, from a different angle and a different distance.  The 100% crops in this A900 section are from the extreme corners.  Printed out as you see them on your screen would measure 65″ (1.65m) wide!

 

Comparison shots below.

 

Sony @ 70mm, F/2.8
Minolta @ 70mm, F/2.8
october08/s28b.jpg october08/m28b.jpg
Sony @ 28mm, F/2.8
Minolta @ 28mm, F/2.8
october08/sw28.jpg
october08/mw28.jpg

 

This is a comparison between the Sony 24-70mm CZ, and Minolta 28-70mm G lenses.  Starting at the top, at 70mm, F/2.8, the Minolta shows more veiling haze, which causes the color cast and wipes out some of the detail.  Look at the trees in the background.  There’s still some difference at F/4, but not much.  When both are set to 28mm, the differences are very minimal, but I think the Minolta may be slightly sharper if you examine a test chart shot at 100%.  The cropped images were taken at infinity focus.

Conclusion. 
For APS-C users; the Sony 24-70mm F/2.8 Carl Zeiss lens performs very well at all focal lengths and apertures.  The corners are nearly as sharp as the centers, even at F/2.8.  Light fall-off, color fringing and coma are basically non-existent.  There is only one issue, flare and ghosting is not controlled very well, so watch out when the sun is near the image, solve this by using your hand to block the light.  When the sun is part of the image, try to center it to mitigate ghosting.  The 35mm equivalent for this lens is 36-105mm, which makes it (just barely) in the wide angle category.  If you’re looking for a high quality fast zoom with this focal range on your APS-C camera, look closely at the Sony DT 16-50mm F/2.8 SSM, it’s much less expensive(-$1200), and has a more useful zoom range, (24-75mm equiv.) in my opinion.  For people wanting a sharp, well performing lens, but don’t really need a constant F/2.8 aperture, consider the excellent Carl Zeiss 16-80mm F/3.5-4.5.
For full frame users; This is a great lens, and is slightly better than the Minolta AF 28-70mm G.  It has a much better close focus ability, veiling haze is controlled better, AF speed is faster, and quieter, it’s sharper in the centers at 70mm, it’s a little wider at 24mm, and the bokeh is slightly smoother in my opinion.  In favor of the Minolta; light fall-off is less at the wide end, it’s not so heavy, and it has an internal zoom, which makes it easier to rotate, and allows a better overall balance.  It also may be a tiny bit sharper at the wide end, but only visible blown way up on a computer screen.  Sharpness differences between the two lenses are very minimal.
This lens is designed for people who use their cameras everyday for a living, and/or find themselves in very demanding environments, like Paparazzi, or news photographers.  You’re paying a lot of money for the extra light gathering power and build quality.  For fair weather photographers on a budget; you probably don’t need this lens, get the Sony 28-75mm F/2.8, or Tamron 28-75mm F/2.8 which provides sharp pictures too, see the comparison review here.  All others; if you have the cash for the Sony Carl Zeiss, go for it, you’ll be happy.
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