siejones
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So I am trying to decide between macro lenses for a sony alpha mount.
The Sony 100mm f2.8 is way over priced as are most sony lenses so I am trying to avoid it. Sigmas potentially have focus issues with SLT's. So I am trying to decide between the Tamron 60mm F2 and the Tamron 90mm F2.8.
Ok here's the issues I am battling with.
* The 60mm is short for a macro but APC crop translated to 90mm but working distance comes into question but considering the 90mm focus barrel extends and the front element is so far recessed into the barrel when you look at the stats the working distance of the 60mm (internal focus and front element is not recessed) is actually very slightly more than the 90mm.
* The fact that the 60mm is faster @ F2 is nice but it raises concerns as to where the sweet spot sits and where diffraction kicks in. Presumably the sweet spot should be Around F4 and diffraction should start earlier than an F2.8 would. Consider macro normally starts @ F11 then are we looking at a lens that has worse diffraction at F16/F22 than an F2.8 lens would? So reviews seem to back this up but I don't know what to believe or just how much worse it actually is.
* Contradicting the above is the fact it is a shorter focal length and therefore more apparent DOF. So would I have to stop down less for the same of DOF than I would at a 90mm. So does this counteract the above problem.
Hope you understand my jabbering.
Cheers
The Sony 100mm f2.8 is way over priced as are most sony lenses so I am trying to avoid it. Sigmas potentially have focus issues with SLT's. So I am trying to decide between the Tamron 60mm F2 and the Tamron 90mm F2.8.
Ok here's the issues I am battling with.
* The 60mm is short for a macro but APC crop translated to 90mm but working distance comes into question but considering the 90mm focus barrel extends and the front element is so far recessed into the barrel when you look at the stats the working distance of the 60mm (internal focus and front element is not recessed) is actually very slightly more than the 90mm.
* The fact that the 60mm is faster @ F2 is nice but it raises concerns as to where the sweet spot sits and where diffraction kicks in. Presumably the sweet spot should be Around F4 and diffraction should start earlier than an F2.8 would. Consider macro normally starts @ F11 then are we looking at a lens that has worse diffraction at F16/F22 than an F2.8 lens would? So reviews seem to back this up but I don't know what to believe or just how much worse it actually is.
* Contradicting the above is the fact it is a shorter focal length and therefore more apparent DOF. So would I have to stop down less for the same of DOF than I would at a 90mm. So does this counteract the above problem.
Hope you understand my jabbering.
Cheers
