GH1 Aperture Priority mode with manual lens

rambooc1

rambooc1

Well-known member
Using a Canon FD manual lens in motion picture mode and aperture priority exposure selected, the GH1 allows a +3 or -3 exposure compensation using the front dial. Can someone explain to me what is being changed when the setting this dial? Obviously the shutter speed is altering exposure, but is the ISO also changing when using this +3 -3 dial?

Reason i ask, i don't have the kit lens and want to use the GH1 with a manual wide lens (20mm) set at infinity focus and do whip pans allowing the exposure to change from whip scene to whip scene (which it does very fast, much quicker than i could manually adjust) . This allows me to have both hands available for stabilizing (holding) the camera (as you can see in the photos i'm using the removable center column from the Velbon Sherpa tripod which i use for compact travel)

I'm not concerned about shutter speed changing for this project, but i'd really like to know what the compensation dial does in this situation.

Thanks

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MR Fanny said:
it should only adjust shutter speed. ISO should be locked unless it is set at AutoISO.
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So what your saying is the camera automatically adjusts shutter as i move and the exposure compensation also adjusts it or presets it higher or lower depending on how much compensation.

ISO is set manually to 100 not auto.

I'm guessing what i'm asking hasn't been explored yet or how the GH1 works exactly is still unknown.
 
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Hey, Rambooc. Which m4/3 adapter are you using for the Canon FD lenses and where can I get it? Also, are you pleased with the adapter you bought? Any problems? Does it focus exactly to infinity? And is it perfectly tight or does it have some wiggle? Thanks.
 
Anyone want to have a crack at my question in the original post and post 3, i imagine there are a few of us that would like some clarification, thanks.
 
rambooc1 said:
So what your saying is the camera automatically adjusts shutter as i move and the exposure compensation also adjusts it or presets it higher or lower depending on how much compensation.
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yep, to be honest thats how it works with the auto kit lens. I'm not sure how it works with manual ones on aperture priority. what are your findings? do you see exposure adjustments with your canon lens? does it communicate with the body?
 
MR Fanny said:
what are your findings? do you see exposure adjustments with your canon lens? does it communicate with the body?
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No it's a dumb mechanical lens no communication with body. But exposure can be altered in 4 ways.

1. Aperture ring on FD lens.
2. Shutter speed on body.
3. Exposure compensation +3 to -3 with the front body dial.
4. ISO adjustment on body.

My question still is, what is the thumb dial adjusting when +3 to -3 is changed in the moving picture mode and aperture priority (A) mode in Exposure menu (PASM)? Is it the same result as with the kit lens?
 
-3 to +3 is like adjusting gain, artificial in a sense to my understanding. it could well be related to ISO to some degree but not directly.
 
ISO is gain on a digital camera. What i want to know is this what is happening, you seem as clueless as me....and guessing with your answers......haha

Thanks for trying anyway, looks like nobody knows and i'll have to find out myself.
 
hey, don't give up on us yet! it's the middle of the night in most of the US, and god know what hour in europe...i'm interested in this as well, so i'll try something when i wake up, in about 8 hours...
 
Yep read that site, but...... how does the GH1 do it. ISO or Shutter speed in the situation in the original post?

Do i hear Barry Green tapping on the keyboard???
 
i wrote a reply then confused myself re-reading your first post....so I am going to hand ball it to Barry too =)

my answer still stands that in aperture priority shutter speed changes and when you dial the -3 +3 meter it adjusts exposure compensation as to how it is explained in that link so it is not related to ISO which is fixed.

had to test myself so put on a manual lens pointed it to tv (sbs james may and his beer adventure on tv), in aperture mode tv shows flickering signs of auto shutter speed, in manual mode shutter speed at 1/50 no flicker.
 
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Haha... good one. Here's another fascinating find. In the same scenario above, pressing AE lock also locks the ISO, so all three (shutter,aperture and ISO) are linked somehow. I think you are right about the shutter changing. Exposure compensation can be either shutter or aperture depending the mode you're in, but when your manual lens aperture is deliberately closed down, it looks like ISO kicks in to compensate (just like a REAL video camera )

.....i think hahaha......... Barrrrrryyyyyyyyy
 
rambooc1 said:
So what your saying is the camera automatically adjusts shutter as i move and the exposure compensation also adjusts it or presets it higher or lower depending on how much compensation.
ISO is set manually to 100 not auto.
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I think this is spot on. Camera has to change some basic exposure parameter in order to adjust exposure by a given EV value. Since you are in Aperture Priority mode (and have a manual lens anyway) it cannot adjust aperture. So that leaves it with ISO and shutter speed. Since you've hard set ISO value the only thing that can logically change is shutter speed. It can be argued that camera still tries to adjust ISO even if a hard value is set, but then consider what happens when ISO is set to 100 and EV adjustment is to underexpose by two stops. ISO is at a [low] ceiling, so physically impossible to adjust further, so camera probably always adjusts shutter speed, as it's only parameter it can touch without much limitation (except for whatever the slowest shutter speed allowed in A mode is).
 
P. Harrill said:
A quick off-topic, but important, note: Have you checked the lugs on your camera to make sure they're ultra-solid? If not, you might not want to use that camera strap as you are in that last photo. Lots of reports of broken cameras thanks to poor design of the neck strap lugs.

http://dvxuser.com/V6/showthread.php?t=187566
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Yes i read about the lug issue, i only use the straps to steady the camera not to carry it. Thanks. I travel a lot so i have to make use of the limited gear i can take, that's why i use the tripod head and removable shaft as a steady device and it works quite well.

@svecher , yes from further testing i think you are spot on with that explanation and using the AE Lock seems to lock ISO as well. Thank you.
 
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