Warren, is your 300/5.6 closing up to f/32? If not, you should be concerned about underexposing with one stop when setting the aperture from the body. This is due because the body mistakenly takes the maximum 5.6 for 4 and will mistake every other aperture with one stop. You can already simulate the behaviour of *ist d with a camera capable of setting the aperture from the body, like Z1-p, MZ-7, etc. if you have one. Take an exposure reading with the aperture set from the lens, and a second one with the aperture set from the body.
From the Adaptall-2 KA adaptor manual: "when using Tamron lenses with a maximum aperture of f/4.5 or slower (maximum aperture at wide end) in the program AE oe shutter-priority AE position [my note: this is always the case with *ist d], underexposure can be cause if the indicated aperture value in the viewfinder is faster than the original maximum aperture value (f/4.5 or slower). In this case please use aperture priority AE or Manual modes [my note: which the *ist d does not support with aperture set from the lens ring]". As for the 500/8, this will behave like a K/M lens, that is you can take pictures with it in Av/M modes if you enable the custom function that unlocks the shutter if the aperture ring is not on A. Apparently you won't be able to use the meter in manual mode. All other lenses you mentioned should be okay. Servus, Alin W. wrote: WX> In Boz' wonderful page he explains the difficulties WX> with using Adaptall mount lens with the KA adapter. I WX> don't quite understand what he is saying. I have a WX> bunch of Tamron lens that I want to use on my new *ist WX> D (in the future of course) but don't understand what WX> limitations they will have. I have a 17/3.5, WX> 35-105/2.8, 80-200/2.8, 90/2.5, 180/2.5, 350/5.6, WX> 400/4, and 500/8. What are the practical limitations WX> on use of my Tamrons? I looked back in the archives a WX> couple of years but came up with only the info below. WX> Please help. WX> Warren WX> <<<http://us.f144.mail.yahoo.com/ym/ShowLetter?YY=13073&order=up&sort=date&pos=1 WX> The Tamron KA Adaptall Mount WX> When Joachim Hein read the above discussion, he WX> immediately understood the roots of the exposure WX> problems that some Adaptall lenses have. These are all WX> "slow" lenses with minimum aperture setting of f/22 WX> and an "AE" setting or f/32 and no "AE" setting In the WX> latter case, f/32 is converted to "AE"). "AE" is the WX> Tamron equivalent of the Pentax "A" setting. Looking WX> in the second column of the table above, we see that WX> there is no contact pattern for lenses with apertures WX> ranging between f/4.5 or slower and f/22. Tamron WX> solves this by making the Adaptall mount indicate a WX> maximum aperture of f/4 and warning in the mount WX> manual that the photographer must watch the aperture WX> read-out in the view-finder (not available with WX> P30/P50!) to ensure that only values within the true WX> aperture range are used.>>>
