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Tokina 17mm 3.5 RMC first impressions (SAMPLES ADDED)
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PostPosted: Mon Feb 04, 2008 3:29 pm    Post subject: Reply with quote
Flor27 wrote:
ChrisLilley wrote:
Flor27 wrote:
You just can't compare a 17mm DX with a 17mm FullFrame Wink

You can if the FF lenses were tested on crop cameras, which is what photozone.de does.

Of course it was, but I guess FF wide angle lenses has more drawback than EF ones for the same focale lengh.


Why? On the minus side, its heavier than it needs to be if it was redesigned for DX, sure. On the plus side, it has a sweet spot effect, which would make it perform better than a FF review. Apart from that it seems perfectly reasonable to compare them as long as the terms of reference are the same.

The point of the MTFs I posted was that the Tokina clearly has some resolution issues, which the MTF shows. It also has some contrast issues, which the review notes but those graphs don't show. I also added the Nikkor 20mm (but the AF version, didn't find tests for the MF version) since Richard mentioned that.

I was replying to Patrick's point about comparison with short zooms. I added the MTF for my own kit zoom because it illustrates the dilemma. Basically I use it as an f/5.6 18mm AF. If I want something that has usable MF and doesn't wobble (really) then I either need to accept a substantial drop in image quality or go for a very expensive AF short zoom (which also has MF capability).

Sad conclusion seems to be that for decent image quality on a crop camera below 24mm, the MF primes are not there. I'd be happy to be shown to be wrong Smile and even happier to be shown to be wrong at a price point under 400 euro.

Richard said the Tokina didn't sing. What does sing at around that focal length?


PostPosted: Mon Feb 04, 2008 3:35 pm    Post subject: Reply with quote
Richard_D wrote:
Chris - I'm beginning to wonder about these photozone tests. I can't comment on the 18-55 figures because I've only briefly used one, but I owned the 20 2.8 AFD (before selling it to buy the (IMO) superior 20 2.8 AIS) and I can't believe it had poorer MTF than the Tokina.


Photozone.de mentioned contrast as the worst issue with the Tokina. There was another thread on this forum about sharpness; contrast seems to play a big part in it. However, they don't publish test results on contrast, only on resolution.

The MTF shows the 20mm slightly worse in the center (which I hadn't noticed until you commented on it) but better in the border and corners. The contrast is also I suspect much better. lastly the Nikkor 20mm has close-range correction so in real world use it will give better results on closer subjects.

I wish photozone.de would test more MF lenses.


PostPosted: Mon Feb 04, 2008 3:52 pm    Post subject: Reply with quote
MTF tests made on crop cameras are not useful in my opinion. A lens must be really horrendous to perform badly on crop cameras. This is especially true for wide angle lenses. Crop cameras are big equalizers.

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PostPosted: Mon Feb 04, 2008 4:06 pm    Post subject: Reply with quote
Orio wrote:
MTF tests made on crop cameras are not useful in my opinion. A lens must be really horrendous to perform badly on crop cameras. This is especially true for wide angle lenses. Crop cameras are big equalizers.

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I agree that crop cameras can hide the flaws of lenses that perform well in the centre and badly at the extreme edges. But that doesn't make the tests useless, far from it. Assuming that the interest is in what lens to buy that will perform well on your camera, rather than comparing lenses in the abstract.

And there are also certainly big differences in the performance of the lenses on crop cameras. So I find your statement to be too sweeping.

Of course if your main interest is in FF cameras, or a mix of crop and FF cameras that have the same mount where you want to exchange lenses, you will want to look at different tests.


PostPosted: Mon Feb 04, 2008 4:10 pm    Post subject: Reply with quote
ChrisLilley wrote:

I agree that crop cameras can hide the flaws of lenses that perform well in the centre and badly at the extreme edges. But that doesn't make the tests useless, far from it. Assuming that the interest is in what lens to buy that will perform well on your camera, rather than comparing lenses in the abstract.


I completely agree. I explained myself poorly. What I wanted to mean is that they are not useful to establish which lens is better in absolute terms - since this seemed to be the point in case here.

For users with a crop camera, yes, tests made on crop cameras are the most useful.

However, I still think that crop cameras are big equalizers when it comes to lenses. They narrow the differences between the lenses.
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PostPosted: Mon Feb 04, 2008 4:57 pm    Post subject: Reply with quote
Orio said:

Quote:

However, I still think that crop cameras are big equalizers when it comes to lenses. They narrow the differences between the lenses.


That can be a very good thing , especially for those on a small budget who dont need wall sized prints. Very Happy Very Happy


patrickh


PostPosted: Mon Feb 04, 2008 4:59 pm    Post subject: Reply with quote
PS

I still stick to my conclusion of the Tok 17 - it's a very decent lens for the money but relatively soft pretty much through its range. However, it does produce very reasonable images and often where there are few options at an affordable price.

patrickh


PostPosted: Mon Feb 04, 2008 5:05 pm    Post subject: Reply with quote
patrickh wrote:

That can be a very good thing , especially for those on a small budget who dont need wall sized prints. Very Happy Very Happy
patrickh


Absolutely yes, and with the 12 Mp of a 450D, you can also make a good 50x70 poster print like you would make with a 5D.

Where you lose -a lot- is in the quality of the wide angle shots, because to obtain an angle comparable to full frame 18mm or 20mm, you need to use fisheye lenses that force you to heavy software corrections, with consequent loss of quality - not to mention that the wider the lens, the worse the resolvance, so also the image quality will suffer - just as in fact is suffers when using a 25mm or 28mm lens to obtain a picture that on full frame a 50mm lens (with much better IQ) would give you.

So there is a tradeoff for the advantage of using the sweet spot of a lens - the difference is that advantages and disadvantages with crop cameras are more related to factors like focal lenght, than they are to actual lens quality.
So ultimately you get both advantages and disadvantages, at a cheaper price.

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PostPosted: Sun May 24, 2009 2:34 am    Post subject: Reply with quote
I have been re-reading this thread because there is one on ebay Click here to see on Ebay.de although the price is now GBP 102 with 11 hours to go.

I don't have a lens wider than 20mm currently, which is not especially wide on DX. Re-reading my comments (and thesee comments), and the reviews, I would be better buying another kit lens rather than going for the tokina. The low contrast is not necessarily a problem, but the soft resolution would be.

And yes I'm not supposed to be buying lenses at the moment.


PostPosted: Mon May 25, 2009 10:49 pm    Post subject: Reply with quote
ChrisLilley wrote:
And yes I'm not supposed to be buying lenses at the moment.


Laughing Laughing Laughing
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