Tamron 60mm F2 Macro concerns

Started May 28, 2012 | Discussions thread
OP siejones Forum Member • Posts: 58
Re: Tamron 60mm F2 Macro concerns

copejorg1 wrote:

The bottom line is that no lens should be any more affected by diffraction at any given f/number than any other lens. But calibration issues, which result in a larger or smaller physical apertures than would be correct for a given f/number (and which, therefore, also affect the DOF being achieved at that indicated f/number) can have a very significant effect.

I'm not sure whether any of the above helps you in making your lens decision, but hopefully the extra info was helpful in some way.



Yes this was very useful thank you.

I too saw the discrepancy between the two photozone review's but didn't quite understand what is going on.

You have explained why diffraction does not come into question here which is great. But what I am still unsure of is the fact that lenses tend to perform better around 2 stops down from wide open then start to fall off. Does this same phenomenon effect an f2.0 lens at say F16 compared to an f2.8 lens and the same aperture. Should it be a concern or too little a difference to be concerned about?

Dave Oddie wrote:

For the Tamron 60mm it is 101cm from the front element and for comparison the Sony 100 it is 157mm.

Sticking those distances into a depth of field calculator gives:

60mm @ F8 @ 101mm = 4mm

100 @ F11 @ 157mm = 4mm

So you can shoot the 60mm roughly a stop wider and get the same d.o.f. (such that it is!)

I am sure I read somewhere on higher mp sensors at aps-c size lenses suffer de-fraction sooner anyway so it may be the Sony starts to see it sooner on a 24mp sensor anyway. Kurts tests are on 16mp or 12mp sensors.

Yeah I realise the higher mp sensor also contribute to greater diffraction but I am sure if you were to resize the 24mp image to 16 or 12mp then it would be comparable so I can live with that.

So you agree with my assumption that you should be able to stop down less which is what I was hoping.

Hmmm 93% and rising I think

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