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Lens Sample Variation


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Quite a broad question that I believe cannot be answered broadly. 

which specific lens are you looking at, which maker (ie Zeiss, Sigma, Samyang, Tokina, Tamron, .... ). 

All - including Canon and Nikon - have quality variations, usually less in their pro line(s). 

For instance with Sigma (I own 5 Sigma lenses) I did not find this, no micro adjustment necessary as they were tack sharp from start.

I do also own two (very old!) Tamron zoom lenses, these are not very sharp to begin with and AF fine tune helps but only so much.

 

In general I would recommend to go to a local store and rent the lens you want to buy for a few days.

Only buy if you are happy with it, If not, tell the store exactly why as they may be able to fix the problem.

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If you get issues such as mis-aligned elements, symptoms will be such things as one side of the image being less sharp than the other - the plane of focus isn't parrallel with the sensor. Focus fine tune will only work if the plane of focus is parrallel with the sensor. 

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Thanks for your answers.

 

The lens I'm considering is the Tamron 24-70 2.8 VC USD for use on Nikon. Currently on a DX body but likely to be FX in near future. Looking at the DxO test this lens seems to optically be as good as the Nikon versions with a much lower price tag.

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Thanks for your answers.

 

The lens I'm considering is the Tamron 24-70 2.8 VC USD for use on Nikon. Currently on a DX body but likely to be FX in near future. Looking at the DxO test this lens seems to optically be as good as the Nikon versions with a much lower price tag.

That's an excellent lens. I've been using it for some time now (18 months or more) and it's performed flawlessly with my D800. The VR is very useful - I can often shoot down to 1/15 or even 1/10 of a second at the wide end, which reduces the need for a tripod at dusk. There's a new Nikon 24-70 that has VR, but it's a lot more expensive even than the old one. Further, from memory, test results show that the Tamron is better at the wide end whereas the Nikon (non-VR version) is better at the long end - the Tamron thus suits better how I tend to use it - more at the wide end than the long end.

 

In short - recommended.   

 

Edit: if you're concerned about sample variation, try it on a full frame body if you can as any loss of edge or especially corner sharpness may not be apparently while you're shooting on DX. Apologies if you're already thinking about this! 

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Thanks for your answers.

 

The lens I'm considering is the Tamron 24-70 2.8 VC USD for use on Nikon. Currently on a DX body but likely to be FX in near future. Looking at the DxO test this lens seems to optically be as good as the Nikon versions with a much lower price tag.

That's an excellent lens. I've been using it for some time now (18 months or more) and it's performed flawlessly with my D800. The VR is very useful - I can often shoot down to 1/15 or even 1/10 of a second at the wide end, which reduces the need for a tripod at dusk. There's a new Nikon 24-70 that has VR, but it's a lot more expensive even than the old one. Further, from memory, test results show that the Tamron is better at the wide end whereas the Nikon (non-VR version) is better at the long end - the Tamron thus suits better how I tend to use it - more at the wide end than the long end.

 

In short - recommended.   

 

Edit: if you're concerned about sample variation, try it on a full frame body if you can as any loss of edge or especially corner sharpness may not be apparently while you're shooting on DX. Apologies if you're already thinking about this! 

 

 

Thanks for the recommendation! No need to apologise - I hadn't though of that and it's a really good idea.

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I recall recommending the Tamron 24-70 VC a while back in another thread started by Armstrong and nothing since has changed my opinion. Certainly the copy I got is excellent. I've used it on a D800 and a D800E and it is extremely sharp but does lose a bit of sharpness towards the edges and corners, certainly in comparison to equivalent primes. However. this is to be expected for a standard zoom and would be barely noticeable (if at all)lon a 24MP camera. The VC is excellent - I can shoot handheld confidently at 1/50 sec and have achieved sharp shots as slow as 1/15 (36MP at 100% sharp that is). Nikon's equivalent new VR is massively more expensive (>£1,100 more) and the older non-VC version is about £500 dearer.

 

As for the original question, I have used Tamron lenses since the early 80s (I've had a few of the excellent 90mm macros) and I never had a problem until very recently when I bought a new 70-200 VC Tamron which scored very highly in the dxo tests. However, my sample was back-focusing and no amount of fine tuning worked. I had a very frustrating time with it until I was sure that it was the lens and not my technique or my camera. Optically it was excellent when I focused manually. Anyway I brought it back and had it exchanged no problem (WEX) for the Nikkor 70-200 (on the recommendation of a forum member in fact and a vast number of 5 star reviews) and that is perfect.

 

I am not drawing any conclusions with regard to quality control from this experience as the sample size is way too small and I have also had a bad Nikkor 50mm lens (once) and a few bad Nikon slide scanners many years ago. And I would certainly buy Tamron again. I needed a 70-200 at the time and I needed one I could absolutely trust which is why I splashed out rather than try another Tamron.

 

So I agree with what DHill says - if you can try it on a full frame body, this would really show up any flaws although focusing problems that could be solved by fine tuning (as in your original question) would be evident at the focus point in any case.  What I would definitely recommend is to buy from a dealer that will take the product back without any quibbles if there is a problem - this applies to any equipment purchase of course, not necessarily the lens in question.

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I recall recommending the Tamron 24-70 VC a while back in another thread started by Armstrong and nothing since has changed my opinion. Certainly the copy I got is excellent. I've used it on a D800 and a D800E and it is extremely sharp but does lose a bit of sharpness towards the edges and corners, certainly in comparison to equivalent primes. However. this is to be expected for a standard zoom and would be barely noticeable (if at all)lon a 24MP camera. The VC is excellent - I can shoot handheld confidently at 1/50 sec and have achieved sharp shots as slow as 1/15 (36MP at 100% sharp that is). Nikon's equivalent new VR is massively more expensive (>£1,100 more) and the older non-VC version is about £500 dearer.

 

As for the original question, I have used Tamron lenses since the early 80s (I've had a few of the excellent 90mm macros) and I never had a problem until very recently when I bought a new 70-200 VC Tamron which scored very highly in the dxo tests. However, my sample was back-focusing and no amount of fine tuning worked. I had a very frustrating time with it until I was sure that it was the lens and not my technique or my camera. Optically it was excellent when I focused manually. Anyway I brought it back and had it exchanged no problem (WEX) for the Nikkor 70-200 (on the recommendation of a forum member in fact and a vast number of 5 star reviews) and that is perfect.

 

I am not drawing any conclusions with regard to quality control from this experience as the sample size is way too small and I have also had a bad Nikkor 50mm lens (once) and a few bad Nikon slide scanners many years ago. And I would certainly buy Tamron again. I needed a 70-200 at the time and I needed one I could absolutely trust which is why I splashed out rather than try another Tamron.

 

So I agree with what DHill says - if you can try it on a full frame body, this would really show up any flaws although focusing problems that could be solved by fine tuning (as in your original question) would be evident at the focus point in any case.  What I would definitely recommend is to buy from a dealer that will take the product back without any quibbles if there is a problem - this applies to any equipment purchase of course, not necessarily the lens in question.

 

Thanks - it's good to know that it performs well on the D800's..from what I understand they are the Nikon FX bodies most likely to show up issues with a lens. Thanks also for the recommendation of Wex.

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Lsat year I too had a Tamron 24-70 from WEX which turned out to have asymmetric focus. (Severe blur down one side of the images) When I told them of the problem they sent me prepaid packaging to return the faulty lens and sent out a new exchange lens.

 

I am very pleased with images from this new lens on my Nikon D750.

 

I also have the Tamron 70-200 and it has been fine out of the box.

 

Allan

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Lsat year I too had a Tamron 24-70 from WEX which turned out to have asymmetric focus. (Severe blur down one side of the images) When I told them of the problem they sent me prepaid packaging to return the faulty lens and sent out a new exchange lens.

 

I am very pleased with images from this new lens on my Nikon D750.

 

I also have the Tamron 70-200 and it has been fine out of the box.

 

Allan

 

I'd forgotten that Allan - I recall you mentioning it. It again highlights the need to check every lens carefully for sharpness across the field as well as autofocus. It is also another plus for WEX - they really do treat their customers very well.

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Lsat year I too had a Tamron 24-70 from WEX which turned out to have asymmetric focus. (Severe blur down one side of the images) When I told them of the problem they sent me prepaid packaging to return the faulty lens and sent out a new exchange lens.

 

I am very pleased with images from this new lens on my Nikon D750.

 

I also have the Tamron 70-200 and it has been fine out of the box.

 

Allan

 

Thanks Allan - much appreciated! 

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I read that Stanley Kubrick used to buy 10 lenses and test them to find the best one.  Buying one is a bit of a lottery, I've had much better luck with primes than zooms.  The manufacturer doesn't seem to make much difference, maybe some of them have better QC but they all produce the odd turkey.

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Here's something on sample variation by a very fussy photographer: http://blog.mingthein.com/2014/05/06/qc-and-sample-variations/ In his opinion/experience, sample variation is not confined to third-party manufacturers.

 

And this one implies that reduced sample variation is something you have to pay for: http://blog.mingthein.com/2015/09/12/a-visit-to-zeiss-and-thoughts-on-the-milvus-line/

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