Tamron SP 24-70mm F/2.8 Di VC USD - advice please

[AchimT]

I had another Tamron on an older camera and liked it. So I think I will buy this one. However, I know that some samples of this series have problems, in that the aperture doesn't really change between 2.8 and 4.

I wonder, how can I test this reliably in the store, to make sure I get a good copy?

Thank in advance for all advice

 

[BacktotheFuji]

Test it on a body with depth of field preview. When you press the button you should see the aperture blades close.

 

[Orville]

Test it on a body with depth of field preview. When you press the button you should see the aperture blades close.

+1

 

[AchimT]

Thank you!

Just to be sure, I should check whether the blades close increasingly more as I move the aperture from 2.8 to 4.0, right?

Should they be closing at 2.8 at all, or is it ok if they don't appear to close at all at 2.8 ?

Thanks again for your help!

 

[BacktotheFuji]

f/2.8 is maximum aperture, so the blades should be wide open. You should see them close more as you stop the lens down, but you may not see much of them until until f/4. Obviously at f/11 they should be clearly stopped down.

 

[Orville]

Thank you!

Just to be sure, I should check whether the blades close increasingly more as I move the aperture from 2.8 to 4.0, right?

Should they be closing at 2.8 at all, or is it ok if they don't appear to close at all at 2.8 ?

Thanks again for your help!

Set the shutter to f/4, focus, then press the depth of field button. The viewfinder should will darkern as it adjusts from f/2.8 to f/4. If it does not darken, you have a lens problem.

 

[AchimT]

Thank you Orville and manualfocus-g!