Tamron 17-50 2.8 VC : Soft at 17 mm and f/2.8 in low light

[wogears]

Nish: STOP PIXEL-PEEPING!

 

You will get wound up in this and never take a picture without worrying about focus or whatever. First of all, the Tamron 17-50 has (as all reviews have noted) some very visible curvature of field wide open. It's part of the design tradeoff for a fast zoom. Thus, if you use the central AF area to focus, then re-compose to place the subject away from center, it will look soft. That is the law of optics, not a copy-specific defect. It is NOT back-focus, front-focus, side-focus or even hocus-pocus-focus.

 

If you MUST test a lens, you have to follow a very rigorous procedure. Here's one way. Get a 4x6 foot piece of plywood. Glue pages of sharp text (magazine pages, laser prints etc.) with various colors in the corners, edges, center and partway out. Put a small plastic mirror in the EXACT center. Now hang the target you have made so that it is precisely vertical. Place your camera on a tripod so that you see its reflection in the viewfinder, while filling the frame with the target. Make a series of exposures at varying f-stops and focal lengths. No UV filters, and use soft even light, like an overcast sky. Use a grey card to set exposure, so your images will have the correct contrast. Compare the images in your RAW converter with sharpening turned OFF, then with various values of sharpening.

 

Do I do this? Nooooo. Life is too bloody short. And, even with this procedure, there are too many variables. Visual acuity, auto-focus errors or camera body modules out of tolerance...

 

I notice you do not have a portfolio, on PN or elsewhere. Were I in your shoes, I would go and take pictures. This is not meant to deprecate--we are not judged by our lenses, but by the effect our images have on others.

[david_naylor]

<p>I don't know about your other shots, but in these two shots the camera simply seems to have focused on the doors behind the toys. Remember that the AF sensors are linear and much larger than the squares in the viewfinder.</p>

<p>And the distance seems too large to be a back focus issue, don't you think?</p>

[ozdemir_ozdemir]

 

<p>Hey guys<br>

first of all sorry for my bad english <br>

its an old topic but i ve the same issue with my tamron 28 75 and pentax k-x<br>

and decided to join photo.net to write that :)<br>

actually Les u are right maybe Nish doesnt have portfolio</p>

 

<p>but its obvious that he s not happy and not comfortable with his equipment <br>

and when u are not happy with it u dont go and take photos or share them with others <br>

i dont think its pixel peeping <br>

maybe he simple needs to be said that <br>

"hey Nish sorry this lens or all dslrs suck in low light or hey come on maybe u bought a fast lens but u cant use it at the widest aperture stop it down man :) or fire the flash no matter how clean ur images at high iso settings :D" <br>

anyway i took some photos with my compact camera and with my tamron lens and decide that <br>

dslrs of course better but when u wanna shot about 5 meters with wide angle that dof stuff may cause problems with aps c sensor and for small 1/2.3 " sensors focus on everytime cuz they dont have any other choice becuz of depth of field lol <br>

whatever i really wanna learn what did u do with that tamron lens :)</p>