16-80cz and 70-200G

[adakshi]

Hello,

I am currently having SAL18250, 70-200G and 50 1.7. Compared to the 70-200G and 50 1.7, 18-250 looks bit dull and slow(aperture). I am thinking to give up the superzoom as I am already covered till 200mm. Now, is 16-80 better than 18-250 in 18-80 range, IQ wise? apart from speed?

Or should I keep the 18-250 as 1 lens solution and buy 24-105 f/4 as prime workhorse when it is available?

What do you suggest?

Thanks
Ayan

[KevinBarrett]

The SAL 18-250 is easily the best lens in its class, but the super-zoom category is full of lenses that are riddled with compromises...that said, the SAL 18-250 is sharper and faster within its range than the SAL 16-105. But then, a 16-80Z + 70-200G would be a dream kit for anyone. It's a tough decision...I wish I had to make it!

[adakshi]

The SAL 18-250 is easily the best lens in its class, but the super-zoom category is full of lenses that are riddled with compromises...that said, the SAL 18-250 is sharper and faster within its range than the SAL 16-105. But then, a 16-80Z + 70-200G would be a dream kit for anyone. It's a tough decision...I wish I had to make it!

Thanks Kevin,

I am spoiled by the 3D look of 70-200G pics. It's hard to go back to 18-250 once you use a G or CZ. I like CZ colors and contrast and from CZ samples I do see same 3D look. It's tough for me as well, I am spending too much for my hobby.

I shouldn't have bought the G.

Nowadays I am mostly using either 50 1.7 or 70-200. Its a strange repulsion toward 18-250. Thank god I don't have 135Z or 85Z.

I have read David's review comment on Tamy 18-250 and that lens is on par with CZ, but still I seek suggestion from 16-80 users

Thanks
Ayan

[Philip]

Ayan, you haven't said which Alpha you're mounting these lenses on. My experience with the 18-250 compared to the 16-80 on an A700 is that I sold the 18-250 (use the 16-80 with a 70-300 G)! In all seriousness, with my lenses there was a small difference in quality at 12mp (18-250 softer and less contrast) but for travelling light you couldn't beat it. Not an easy decision - only you know whether you need the perceived small gain in quality compared to increased kit weight

Philip

[aster]

Hi,

I'll speak in favour of the CZ 16-80 but only because I own one. I used it frequently enough ( 9000+ shots) to realize that I have a good copy in build and optical assembly wise. If you're used to the G quality-lenses this lens will be a good equivalent. Travelling may demand other approaches with good zooms like the SAL 18-250 but I own the SONY SAL 18-200mm and since I purchased of the CZ 16-80mm I never attached the 18-200 to the camera. But of course it should be pointed out that 18-250mm is a better version of the 18-200 which came as a kit lens in the first place.

Yildiz

[adakshi]

Ayan, you haven't said which Alpha you're mounting these lenses on. My experience with the 18-250 compared to the 16-80 on an A700 is that I sold the 18-250 (use the 16-80 with a 70-300 G)! In all seriousness, with my lenses there was a small difference in quality at 12mp (18-250 softer and less contrast) but for travelling light you couldn't beat it. Not an easy decision - only you know whether you need the perceived small gain in quality compared to increased kit weight

Philip

Thanks Philip,

I am using A700. Eventually go to full frame, may be after 5 years.

Thanks
Ayan

[David Kilpatrick]

That was Philip's decision. We have a 16-80mm and 70-300mm - but Shirley prefers to travel and shoot light, one lens if possible. So we bought Philip's 18-250mm - it's fine in the sort of conditions we normally shoot (sunny, daytime). I did try it on the A350 and felt it was not quite good enough. It was excellent on Shirley's A200, now she has the A700 it's not quite resolving enough for the sensor at the 250mm end.

In February, we lent our daughter the A350 with 16-80mm and 55-200mm Tamron. First, the results were SO much better than her Canon 400D she didn't want to give the camera back, and since they used both cameras together, I was able to see the results on their 42 inch plasma screen - the A350 is in a totally different class in every respect, exposure accuracy, colour quality, focusing - the lot. So at Focus on Imaging I have bought her an A350 body for £299, I will be letting her have our 16-105mm which was intended to be sold (as new), and taking her Canon 400D with two lenses to go into my cupboard as a test body (I have no Canon body at present). The big problem is knowing what long lens to get her, but the the Tamron 55-200mm seems ideal. It is exceptionally sharp and the images they got with it were great, and it only costs £70 or something like that.

David

[travelingman]

That was Philip's decision. We have a 16-80mm and 70-300mm - but Shirley prefers to travel and shoot light, one lens if possible. So we bought Philip's 18-250mm - it's fine in the sort of conditions we normally shoot (sunny, daytime). I did try it on the A350 and felt it was not quite good enough. It was excellent on Shirley's A200, now she has the A700 it's not quite resolving enough for the sensor at the 250mm end.
David

I have both an 18-250mm and an CZ16-80mm that I have been using on my A200. Frankly, the CZ16-80mm is driving me a little crazy. I can't figure out if I should sell the lens or the camera! When it nails the AF, the A200/CZ is clearly better than the 18-250, especially wide open. The exception might be at 50mm where they seem to run neck and neck. Unfortunately, the CZ seems to miss the AF at the wider half of the range more often than the 18-250mm, and when it does it is not worth its price tag.

David, I've read your post about the CZ needing less contrasty edges to focus more accurately, and maybe that is part of my problem. However, I am not a professional photographer and I don't want a lens and body combination that requires me to thinking about whether or not my subject is going to satisfy the AF needs of the CZ lens.

I had a slight backfocus bias with the A200, and I've adjusted that out with the three adjusting screws on the camera bottom, and that did seem to make the shots at the wider range sharper, but only when it was obvious the AF was correct.

I guess my question is this. Is there anything about the A200/CZ combination that is going to result in less accurate, less consistent focusing than with the A300, A350, A700? Should I hang on to it until I have a camera that will do a much better job of AF?

I got that CZ lens at a great price through Circuit City's demise. I have no reason to believe there is anything wrong with the lens, and the A200 is merely a bridge camera for me, so I will most likely upgrade when I know more about Sony's rumored new models. But if the CZ lens is going to be tempermental about focusing, even with a camera with improved focus, then I might sell it now while it's value is still high.

[David Kilpatrick]

Here is how to check your 16-80mm:

Set the camera to MF, and study the focus confirmation light in the finder, while focusing on some targets at 16mm. See how much RANGE there is, during which the light is on. Note the range down from the focus scale. Now try autofocusing on the same target and see where the camera ends up - whether it is in the middle of the range, or tends to be at either end.

Try focusing on a close subject then moving to a distant one. Compare this with the focus after you turn on (always starts from infinity).

This may help you understand why some shots are not right. It will not be any different with a 300 or 350, but on a 700, accuracy is much improved.

David

[travelingman]

Here is how to check your 16-80mm:

Set the camera to MF, and study the focus confirmation light in the finder, while focusing on some targets at 16mm. See how much RANGE there is, during which the light is on. Note the range down from the focus scale. Now try autofocusing on the same target and see where the camera ends up - whether it is in the middle of the range, or tends to be at either end.

Try focusing on a close subject then moving to a distant one. Compare this with the focus after you turn on (always starts from infinity).

This may help you understand why some shots are not right. It will not be any different with a 300 or 350, but on a 700, accuracy is much improved.

David

David,

Thanks so much for the prompt reply. Since the sun has set here, I was only able to perform this test in my office, but the results were still interesting and probably predictable.
First, I used the CZ16-80mm lens. I chose a target whose actual distance was 9ft. I checked autofocus with the lens zoomed in, i.e. 80mm. It nailed the focus exactly everytime regardless whether I was coming from infinity or close-up.

Then I switched to manual focus and zoomed out to 16mm. I got a confirmed focus light from about 5ft to infinity. Then I switched to autofocus, and did tests infinity. The autofocus landed pretty much where it started, i.e. infinity. Then I repeated the test from a near focus position. The autfocus landed just short of infinity. Repeated all these tests several times and got consistent results. Clearly there is a bias to focusing beyone the target.

Then I repeated this same set of tests with my Sony 18-250mm lens. Results were very similar. Target was the same and AF nailed it exactly when zoomed in. At 18mm, manual focus produced a light on condition from 9ft to infinity. Autofocus from infinity was just shy of the infinity mark, so well beyond the actual distance. Focus from close-up was slightly better and landed about 1/2 the distanced between the 100ft mark and infinity.

This data suggests both lenses are performing similarly, although my perception was that the 18-250 at 18mm was focusing more accurately than the CZ at that same focal length. The distance scales on the lenses are such that it would be very difficult to see if the errors are mathmatically the same percentage on both lenses.

Seeing how both lenses are overshooting the actual target distance, and are even baised to the more distant end of the manual focus range, the question now is should I tweak the AF screws on the camera even more, i.e. to bring the focus more forward, or will I risk messing up focus at more sensitive distances and focal lengths? Right now I would say I have neither a front or rear focus bias on the screw settings.

Thanks

[David Kilpatrick]

I would suggest that you rely on autofocus when using apertures of f8 or smaller (i.e. f11, f16 - smaller apertures, not smaller numbers the way some people say it).

When you are using wider apertures, use manual focus for critical subjects and position the focus in the middle of the range. I have now tested a number of different cameras and my findings are that autofocus just does not work with wide angles. If it looks sharp, it is luck. Nothing more. The depth of field is so great that the AF setting is almost random. You are better off setting the lens by guessing and using the focus scale.

I wish this was not so, but it is. The 18-250mm looks sharper because it has more aberrations in the spherical domain - it does not have an exact plane of focus to the same degree the 16-80mm does. So it's a softer lens looking less defocused, not a lens looking better focused.

David

[artington]

David said

I have now tested a number of different cameras and my findings are that autofocus just does not work with wide angles

Very interesting observation, David. I remember reading (and I think there is a theoretical basis for this) that rangefinders are best below 90mm and SLRs above this focal length. Now we are in the digital world this is hard to put into practice because the only digital rangefinders currently in production are the two Leica M8 variants and both of these have 1.3x mag factors. (Cosina has announced the Epson RD1x, based on the RD1 but with a bigger rear screen, but this has only 6mp and a 1.5x magnification factor). So, to get the benefit of wide angle on digital RF you have very large expense indeed because neither the M8 nor the Leica superwide M fit lenses come cheap!

[travelingman]

I have now tested a number of different cameras and my findings are that autofocus just does not work with wide angles. If it looks sharp, it is luck. Nothing more. The depth of field is so great that the AF setting is almost random. You are better off setting the lens by guessing and using the focus scale.
David

Thanks David, for the expert opinion. On one hand it is good to know that the wide angle AF problems I am having are not unique to my camera body or lens. On the other hand it is disappointing to spend so much money on technology that at least in this regard is still lacking. All I can hope is that my next camera body will have better AF capabilities. I really hope Sony gives me a reason to upgrade sometime this year.

Based on your comments, I will not sell either my A200 or my CZ16-80mm lens at this time.

Thanks again

[David Kilpatrick]

I should add that f/2.8 sensors greatly improve wide-angle AF if you have an f/2.8 WA lens. If you read my review of the Tamron 10-24mm f/3.5-4.5 on the main website here, you will see some examples of how great the real depth of field of a lens at 10mm is when stopped down - huge focus errors are hardly visible. You will also see that f/3.5 is not a good aperture! Tokina's 11-16mm f/2.8 is much better because it switches on the f/2.8 central sensor of the A700 (or it would if they made it in Alpha mount) and thus doubles - or more - the focus accuracy.

My 17-35mm which never focused well on A100 was improved by A700 but even more so by the A900, which seems to have a very well tuned f/2.8 centre sensor.

Despite that I am using the Sigma 12-24mm f/4.5-5.6 - really a very slow lens. Focus is not accurate and I do often adjust the setting using the distance scale, or bracket the focus.

Lenses to look out for with the A700 and A900 - obviously the 16-35mm f/2.8 (good reason why they did this!), the 17-35mm f/2.8-4, the 20mm f/2.8 and the 16mm f/2.8 fisheye. For the 700 only, the Tamron 17-50mm f/2.8 (constant aperture), Sigma 18-50mm f/2.8 (ditto) and also the Sigma 17-70mm f/2.8-4. I got very good focus accuracy on the A900 with the Sigma 24mm f/1.8 and their 20mm f/1.8 would presumably be as good.

David

[Dr. Harout]

...Lenses to look out for with the A700 and A900 - obviously the 16-35mm f/2.8 (good reason why they did this!), the 17-35mm f/2.8-4, the 20mm f/2.8 and the 16mm f/2.8 fisheye. For the 700 only, the Tamron 17-50mm f/2.8 (constant aperture), Sigma 18-50mm f/2.8 (ditto) and also the Sigma 17-70mm f/2.8-4. I got very good focus accuracy on the A900 with the Sigma 24mm f/1.8 and their 20mm f/1.8 would presumably be as good.

David

I know you don't like much the 28/2.8 but I think it is worthy to be included in the list.