9th October 2004, 02:17 PM
Stacking teleconverter 1.4x + 2.0x Sigma
Just would like to share one observation today while trying out - out of curiosity on how the performance of the Sigma 70-200mm f2.8 APo lens perform at a worst case desperate double stack of teleconverters. I was trying out on a black and white T-Max so that i could process it at home.
The film was scanned at 1800dpi - although i could have scanned it at 2400dpi ( the highest i could go).
I was just looking at the image at 25% and was kinda curious on what the black area path details would be, to my surprise, even at the max 560mm and aperture stopped down to f11......zoomed at 100% i found that the setup could capture the detail of the wire mesh.....
The camera was on a tripod.....and a cable release was used + Pre fire mirror up....
Foussing was put at MF - and focus verified with a angle finder a 2x...
From the above, it could be seen that the mesh detail is still intact - probably with the help of the tripod + pre fire MLU...
10th October 2004, 08:02 PM
10th October 2004, 08:08 PM
What do you mean by that? The way you say is like the guy who shoot with your mouth. He just want to do some testing and share the result with us, is that against your principle or what?
Originally Posted by smallaperture
If you mean this phrase "The camera was on a tripod.....and a cable release was used + Pre fire mirror up...."
Well, even with Tripod and cable release, there is still vibration from mirror slapping and thus a pre fire mirror up give that extra 2 sec for the camera to stablise. At 560mm a minor shake can show, especially at slow speed.
Last edited by blurblock; 10th October 2004 at 08:13 PM.
10th October 2004, 08:09 PM
Anyway, nice test, using a APO f/2.8 and lost three stops of light will yield F8, thus I guess at F11 the detail should still be quite ok.
Originally Posted by sulhan
10th October 2004, 10:55 PM