Theo Kupfer

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Minolta 7D ADI/PreFlash with non D lenses

I was wondering if the build in distance encoder, which allows the distance measurement even with non (D) lenses also in the manual focus mode, would be used for ADI flash for non (D) lenses. The other possibility would have been that the camera switches to preFlash TTL in the case of a non (D) lens.

To check this I did the following test setup:

I setup the camera about 2 m from a target. Then I made three pictures. First (A) was done with the target in focus. The second (B) was done with manual focus set to twice the distance (~ 4 m). The third (C) was done with manual focus set to half the distance (~ 1 m).

With ADI, I expect the second picture overexposed because the camera assumes the target further away and sets the flash to a higher guide number. The third picture is expected to be underexposed.

With preFlash TTL, I would expect all three pictures to be exposed the in the same way.

I did this with two non (D) lenses and with one (D) lens.

Result:

  In focus (A) Twice the distance (B) Half the distance (C)
2.8/100 Makro (non D)
1.4/85 (non D)
2.8/28-75 (D)

The pictures show that ADI stays active with the non D lenses. Case C is underexposed with all three lenses. Case B is overexposed with the non D lenses but funnywise not much different with the D lens (???).

Flash was a 5600 HS(D).

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