Originally posted by Zealex When using the aperture ring, I see that the camera has no idea what the F stop is. Only when my 50/1.7 A is on A does it show in the LCD screen. Does this prohibit me from using Tv/Av and will I always have to use manual mode?
Also, is it bad to use "weird" ISO values, eg 320, 500, 1250 etc and am I better off sticking to ISO's like 200,400,800,1600..etc?
Thanks for all the help so far, much appreciated.
Edit: When in manual mode the light meter doesn't work for my 135/2.5.
Setting the A50/1.7 to A on the aperture ring is exactly what
will allow you to use (semi-)Automatic modes like Tv and Av.
There's noting wrong with using in-between ISO values. But you might want to standardize on only using every stop or something, in case you ever start using more advanced noise reduction software that requires you to make a profile for each ISO (you only have to make 1/3 as many profiles in that case). Otherwise it doesn't matter much. I only use 80, 160, 320, 640, etc. on my cameras because it seems to work better, but the K-r starts at a different ISO so 100, 200, 400, ... might be better. Run some informal tests and see at which steps the noise gets worse - then you can use all the ISOs just 1/3 stop below each of those.
When the Takumar 135/2.5 is wide open at f/2.5 a number of modes may work, but the rest of the time you want to use M mode, pressing the green button before each shot to set the exposure.
Here are some settings you might want to change or at least consider in the [C Custom Setting] Menu in the camera, if you haven't already (I looked them up in the manual):
1. EV Steps:
1/3 EV Steps
2. Sensitivity Steps:
As EV Steps
3. Expanded Sensitivity:
On (so you can use more ISO settings, including ISO 100)
19. Save Menu Location:
Save Menu Location (convenient for me)
22. Using Aperture Ring:
Permitted (so the shutter will still release when you use your Takumar 135/2.5 or any other lens without the aperture ring on 'A')