Replacing Lens Mounts

ChaoticBob · 10-01-2007, 05:55 AM

I've just found out something interesting, on my DS at least. I noticed that with no lens on the body in A mode, the aperture actuator would move when I took a shot. This is obviously different to how it behaves when there is a lens on, where its wide-open only. I figured out it determines there is a lens there by any one of the A-contacts touching against the lens barrel. By masking this, the body doesn't realise there is a lens attached.

This means that by staying in A mode and using the EV compensation you can shoot up to 2 f/stops less than wide and still maintain auto-exposure. You just set the right aperture on the lens and then adjust the exposure compensation to suit. Unfortunately there is only 2 EVs maximum on the DS, it might work even better on a K10d which I believe has 3 EVs.

The best thing is it still works exactly as before in M mode, so there is almost no downside, the only quirk I have noticed is that Auto-ISO doesn't work. I am planning on trying the nail-polish idea as something more permanent as the tape has a habit of coming off when you mount the lens. Apologies if someone has thought of this before, I found it a great help shooting outdoors, much faster than hitting the AE-L button before every shot.

**Lowell Goudge** · 10-01-2007, 07:41 AM

Originally posted by Ben_Edict

BY THE WAY: manual metering with the K10D can be improved by using an istDS matte screen. I am using now a istD screen with grid and get somewhat better results than before.
regards
Ben

Have you got a sample curve with the origonal and DS screens of grey scale vs f-stop to show the gain?

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10-01-2007, 05:55 AM	#16
ChaoticBob New Member Join Date: Oct 2007 Posts: 1	I've just found out something interesting, on my DS at least. I noticed that with no lens on the body in A mode, the aperture actuator would move when I took a shot. This is obviously different to how it behaves when there is a lens on, where its wide-open only. I figured out it determines there is a lens there by any one of the A-contacts touching against the lens barrel. By masking this, the body doesn't realise there is a lens attached. This means that by staying in A mode and using the EV compensation you can shoot up to 2 f/stops less than wide and still maintain auto-exposure. You just set the right aperture on the lens and then adjust the exposure compensation to suit. Unfortunately there is only 2 EVs maximum on the DS, it might work even better on a K10d which I believe has 3 EVs. The best thing is it still works exactly as before in M mode, so there is almost no downside, the only quirk I have noticed is that Auto-ISO doesn't work. I am planning on trying the nail-polish idea as something more permanent as the tape has a habit of coming off when you mount the lens. Apologies if someone has thought of this before, I found it a great help shooting outdoors, much faster than hitting the AE-L button before every shot.

10-01-2007, 07:41 AM	#17
Lowell Goudge Site Supporter Join Date: Jan 2007 Location: Toronto Photos: Gallery \| Albums Posts: 17,891 Original Poster	Originally posted by Ben_Edict BY THE WAY: manual metering with the K10D can be improved by using an istDS matte screen. I am using now a istD screen with grid and get somewhat better results than before. regards Ben Have you got a sample curve with the origonal and DS screens of grey scale vs f-stop to show the gain?