[snake]

It should be called whatever the physical aperture is, but the usable range would be explained in the sharpness tests.

I have a Soligor 24 2.5, which not much is known about compared to the 2.8 variant that is pretty common. Oddly, it is VERY soft at 2.5, marginally better at 2.8, but only has useful and great sharpness at 5.6 and above.

Had I known this, I would have gone for the Sigma 24 2.8 AF, which is sharp wide open.

It was also this reason I didn't get the FA43 and opted for the FA35 instead- I shoot wide open all the time and I needed something sharper and without that "dreamy character" of the FA43. If I get more creative, I might go for it for portraits.

[Lowell Goudge]

With very few exceptions, i find that the F stop, and actual exposure between (for example 5 different 28mm lenses) is consistent and therefore there is no real need to discuss T-Stops at all. It just confuses the matter. In all honesty, i have only ever found one lens (out of 50 or so that I own, so forgive me if It does not cover any other of the 23million plus lenses out there) that has a need for different exposure at the same F stop, this is an old XR rikenon M42 mount 135 which is one stop slower (based on shooting shutter speed at any aperture) compared to my other 3 135mm lenses. mostly though, the difference in light transmission lens to lens is less than 5% and when you consider a full stop is 50% you can see why I suggest forgetting all about T stops, we do all sorts of other things that cause more than a 10% error in our exposure and this is well within the range of correction (even in JPEG) during post processing.

[eddie1960]

As people talk hoods, one thing to consider in the ASP-C world is that you can gain a ton, by extending the hoods far beyond the stock hoods for most legacy lenses because the hoods were either deisgned for multiple lenses, and they are designed for full frame field of view. I use the hood of my SMC tak 200/4 on my supertak 85 for example,

Steep down 1-2 focal length steps with all your hoods because the light that covers a full frame (film for example) just goes into baffles in the mirror box on a DSLR

I use my 135 hood on my 85 and 50, my 50 hood on 35 and 28. My 28 hood I really only use when shooting film with the 28 and 35.