Lens Quandary Tamron f2.8 17-50 vs 28-75

Stingey said:
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photostream


Right so here are the two images I took today on my lunch. I had very limited time so only got these for the moment. Both took on a tripod with cable release. In between the two shots, as I was changing the lenses, the camera and tripod fell and hit the back concrete step camera first! I've superficially damaged the lens release button and part of the body so could have been worse.

The Tamron is DEFINITELY softer which shouldn't be right.
Here are the settings:-

Tamron at f2.8 1/160s iso 100 @50mm

Canon at f/5 1/50s iso 100 @46mm

I know these aren't like for like but could it be deduced from these images that I have a dud?

Thanks
Click to expand...
Sorry to hear about the camera falling over ....

Your test is pretty much invalid tbh. You would need to compare at the same aperture to be able to determine anything ... in general most lenses are a little sharper when stopped down some.

One thing worth pointing out though is you can at least shoot at f2.8 with the tammy, where you cannot with the kit lens ;) - that could be the difference of getting the shot and not!
 
I thought as much Paul. I might take it somewhere and get it looked at by a pro. I'm too new to this to do the testing justice. Thanks for the advice.
 
So I got this email back from One Stop Digital after I asked to return the lens, what should I do???


Hi,



Thank you very much for your email.



Please note that we do not offer replacement if you believe the lens has back, front or soft focusing problems. Please refer to our terms and conditions for details and explanation on this. In short, these focusing problems are not entirely down to the lens itself, the camera body also plays a part.



We can however send the lens to Tamron for adjustment for you but you would need to send us your lens together with your camera, because Tamron cannot do the adjustment without your camera, as every camera is different.



We have such policy in place as we had sent many of such lenses to Sigma, Tamron and Tokina and almost all of them were found to be not faulty. Sigma would do the adjustment but this would be a charged service, however we can cover this charge for you as a goodwill gesture but you really do have to send us both your camera and lens. We will try our best to return both camera and lens to you as soon as we can.



Alternatively, you can return the lens to us under our return policy, which can be found under our terms and conditions on our website, in which case £18 will be deducted from your refund to cover our shipping cost for sending you the lens from Hong Kong.



Please let us know how you would like to proceed.



Thank you.



Regards,

Onestop Digital
 
I can sort of understand what they are saying, I suspect that they have had many returns that have ended up being attributable to other factors. As for sending them the camera, I wouldn't. Looking at the images on Flickr it doesn't suggest there is an issue with the camera body to me most images are well focussed (the puppy looks like you missed focus btw).

At this point it is difficult to say whether you actually have a problem lens or not. I know you shot on a tripod, but testing a lens is more than a couple of shots at different apertures and doing a comparison by eye ... at the least do a comparison at the same focal length and aperture. If you don't like the results send the lens back and put the £18.00 cost down to experience.

To accurately test you need a good constant light source, a high contrast image and use a single focus point (centre is best). Also use the tripod and if poss a remote or cable release. Some people use batteries stood up in a line, some use rulers and targets, some use proprietary targets like lens align. There are also devices and software out there that will help.
 
I should add that I don't agree with Onestop Digital's policy and had I read that before buying I would buy elsewhere!
 
Where do you get your lenses from Paul? I wanna go into a shop, try one out, look at the images on a computer, decide whether I'm happy or not, then go back and buy the lens, save all this aggro.
 
I go into shops when I can. Last lens came from Grays up in Pimlico in London (I shoot Nikon), previously I've got them from Jessops (RIP), LCE, Mifsuds and the like. Not always the most cost effective way to buy, but I'm a tad conservative at times. I sometimes tale a risk and buy used off eBay too ...
 
I'm based in Bolton near Manchester and it seems there's hardly any shops around. I've found Calumet, it has the lens but it doesn't seem to have the 'VC' option. Do you rate the VC lenses?

Ta
 
When I shot DX I looked at both the then available Tamron 17-50mm lenses, I found the non VC to be sharper than the VC version, not by much though. I do rate the tamron VC system though as it seems to work - but to be fair I haven't owned or used enough of them long enough really, so am probably not the best person to answer that.
 
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