GH2 F stop, shutter, ISO OH MY!!

M

mslade

Member
So here's the deal. No control over light. Have to use what is existing.
Shutter at 60, lens is at f4.5.....(widest it will go)....In order to get what looks like "proper" exposure I have to crank the ISO to 1600. I could also run the shutter down to 30 and the ISO to 200/400 to get the same look but I didn't have time to shoot and review the footage to make sure that a slower shutter wouldn't screw up the footage in terms of jerkiness....stuttering (if too slow)
Assuming I keep the shutter at 60, if my lens would go down to f2 or 2.5ish......what would I be able to drop the ISO to in order to keep that same "exposure".
Crud I hope this makes sense....the more I type it the more I think I'm not asking this right.....

Thanks
Mark
 
I don't know exactly what ISO you could drop it down to, but maybe ISO 400 or even ISO 200. I'm really just guessing since I don't know how much light you're dealing with. Good luck, maybe get a used Canon FD 50m F/1.4 lens with an adapter.
 
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Theoretically speaking, using a lens that was that much faster could get you down to somewhere between 200 and 800, although without seeing what you're trying to shoot and your lens selection it's hard to say. A fast Canon FD prime or the Panasonic 20mm f1.7 would be a good choice, IMHO. I thought the GH2 had low noise through 1600 ISO?
 
CColton said:
Theoretically speaking, using a lens that was that much faster could get you down to somewhere between 200 and 800, although without seeing what you're trying to shoot and your lens selection it's hard to say. A fast Canon FD prime or the Panasonic 20mm f1.7 would be a good choice, IMHO. I thought the GH2 had low noise through 1600 ISO?
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Wish I could use a prime for this......it's a performance on stage that I have to be able to zoom in or out as needed. I was using the 14-42.....I've just been trying to figure out specs for new lenses to buy.....and was wondering how much lower I could get on the ISO going to f2 or so. You're right....the noise isn't bad at 1600......I just want to be able to get the ISO as low as possible. 200-400 will do.....just didn't want to put out $$$$ for a fast zoom and end up only dropping a little from 1600.....

Thanks
Mark
 
I have a Tokina 80-200mm f2.8 (Canon FD mount) that I bought for $275. It's a great lens and will get you the frthest zoom you'll likely need, and f2.8 is a big improvement from 4. A lens like that could work for you.
 
CColton said:
I have a Tokina 80-200mm f2.8 (Canon FD mount) that I bought for $275. It's a great lens and will get you the frthest zoom you'll likely need, and f2.8 is a big improvement from 4. A lens like that could work for you.
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I was just looking at used stuff at B&H. Some promising lenses there.....and I just happen to be going to NYC in 2 weeks. Might have to make a side trip!!

Mark
 
You need some fast glass. Just remember that some lenses are really soft wide open so your 1.4 may only be acceptably sharp stopped down a bit.

It all depends of the lens some are good wide open. I have a 55 1.2 FL and it is really soft until 2 or 2.8.
 
mslade said:
So here's the deal. No control over light. Have to use what is existing.
Shutter at 60, lens is at f4.5.....(widest it will go)....In order to get what looks like "proper" exposure I have to crank the ISO to 1600. I could also run the shutter down to 30 and the ISO to 200/400 to get the same look but I didn't have time to shoot and review the footage to make sure that a slower shutter wouldn't screw up the footage in terms of jerkiness....stuttering (if too slow)
Assuming I keep the shutter at 60, if my lens would go down to f2 or 2.5ish......what would I be able to drop the ISO to in order to keep that same "exposure".
Crud I hope this makes sense....the more I type it the more I think I'm not asking this right.....

Thanks
Mark
Click to expand...

The calculations are 'simple'... if your 4.5 allows you to shoot at 1600, then a 4.0 lens (1/3 stop faster will allow a IS0 1300 (1/3 stop lower ISO), Dropping down a full stop to 2.8, will allow for a 650 ISO value, F-stop 2.0, gives 325 ISO, f-stop of 1.4 gives a 162 ISO... obviously the available 'nearest' ISO would be selected...
 
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