Lens evaluation

cab.in.bostoncab.in.boston Registered Users Posts: 634 Major grins
edited October 26, 2009 in Cameras
I just received a couple of new toys, a Tamron SP AF17-50 f/2.8 XR (non-stabilized version) and a SB600 flash. :barb I'm very excited about my new stuff and can't wait to learn how to use the flash and exploit the wider lens (my previous widest lens was the 35 f/1.8 prime).

I've heard much reported about sample variation in 3rd party lenses, so I want to make sure I really put this lens through its paces quickly so I can exchange it if need be. Problem is, I've never done this before, so I'm looking for some tips of what to do and how to evaluate the results. So far I've mounted it on a tripod and shot a series of photos of some framed Beatles LPs I have on the wall. I shot at 17, 24, 35, and 50mm, at every stop from 2.8 to 32. I used center point AF, matrix metering, and a remote shutter release. No flash, just ambient light. I do not have a high quality printer, so I'm printing out some test charts, but I don't know how well that will work out.

Other than simply looking at the photos I took and using my (untrained) eye, what else should I do to really shake this down before deciding it's worth keeping?

Thanks for helping out a newbie!
Father, husband, dog lover, engineer, Nikon shooter
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Comments

  • ziggy53ziggy53 Super Moderators Posts: 24,132 moderator
    edited October 26, 2009
    I just received a couple of new toys, a Tamron SP AF17-50 f/2.8 XR (non-stabilized version) and a SB600 flash. wings.gif I'm very excited about my new stuff and can't wait to learn how to use the flash and exploit the wider lens (my previous widest lens was the 35 f/1.8 prime).

    I've heard much reported about sample variation in 3rd party lenses, so I want to make sure I really put this lens through its paces quickly so I can exchange it if need be. Problem is, I've never done this before, so I'm looking for some tips of what to do and how to evaluate the results. So far I've mounted it on a tripod and shot a series of photos of some framed Beatles LPs I have on the wall. I shot at 17, 24, 35, and 50mm, at every stop from 2.8 to 32. I used center point AF, matrix metering, and a remote shutter release. No flash, just ambient light. I do not have a high quality printer, so I'm printing out some test charts, but I don't know how well that will work out.

    Other than simply looking at the photos I took and using my (untrained) eye, what else should I do to really shake this down before deciding it's worth keeping?

    Thanks for helping out a newbie!

    Compare the images from the new lens to images from another lens in your kit. Also, try to shoot some images in a situation similar to your intended use of the lens.

    I do include some tests of high-contrast targets, both in the center and with the target at the edge. Traffic control signs (stop and yield signs, for instance) work pretty well for this purpose.

    I also test lenses in very low light, to see how the system, camera and lens, perform AF in low light (often a consideration for my purposes.)

    If you intend to use the lens at close focus, run some tests to gauge AF speed and accuracy at typical distances.

    It's all about trying to evaluate the lens as tool for your intended applications. Testing the lens beyond your intended use is probably not necessary, but if it trips your trigger, have fun.
    ziggy53
    Moderator of the Cameras and Accessories forums
  • Wil DavisWil Davis Registered Users Posts: 1,692 Major grins
    edited October 26, 2009
    snip…
    I do not have a high quality printer, so I'm printing out some test charts, but I don't know how well that will work out.

    Other than simply looking at the photos I took and using my (untrained) eye, what else should I do to really shake this down before deciding it's worth keeping?

    Thanks for helping out a newbie!

    Don't worry about printing out test-charts; here's a way which is much simpler:

    Get a sheet of newspaper (something like from the classifieds of the Boston Globe or some such broadsheet with lots of text and few graphics) and tape it to the wall. You'll need a tripod, although at a pinch you can use a table or something; what you're trying to do here is to take a series of pictures of the sheet of newspaper, each from exactly the same point, using different apertures and zoom-settings in order to test the lens(es).

    Take lots of pictures at various settings, of the newspaper from across the room.

    HTH -

    - Wil

    BTW - Welcome to the Digital Grin Photography Forum

    PS: just noticed that you're talking about wide-angle lenses, in which case you can get even closer to the wall. I'd try to fill the frame with the newspaper, and don't forget any linear distortion will be quite obvious, but that's the nature of the beast ne_nau.gif
    "…………………" - Marcel Marceau
  • divamumdivamum Registered Users Posts: 9,021 Major grins
    edited October 26, 2009
    In the case of the 17-50, take some shots of just about anything in good light (use flash if necessary) at various apertures and then look at them at 100% magnification. If it's anything like the copy I have, it will be so sharp it will take your breath away, and leave you no doubt that it's working properly! Eyes are a good thing to try - with my 17-50, you can not only see every pore detail at 100%, but the lashess practically tickle you as you look at them. Seriously.

    Enjoy. :D
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