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View Full Version : Exposure workaround for newcomers



yoclay
04-25-2009, 01:25 AM
I brought this post of mine over from the Cinema5D forum:

Hello to those who are looking for a workaround in absence of a new firmware update and who are new to this.

What you need is the equivalent form of a portable data input device. This could be an iphone, a computer laptop, a PDA or even a battery powered digital photoframe, anything which you can have a variety of full frame jpegs each a different shade of grey. This is what I do and it works.

For each lens and f-stop, I set the Over exposure dial to +2 and then I play with a grey scale image (using sliders in photoshop) until I find the equivalent of 1/50 sec at 1600 ISO. I always cover the lens entirely with the digital device. I then lock the exposure and dial down the OE wheel to see if the 1/50sec value holds. If it does I usually am able to get down to 100 ISO. Since the light intensity is always the same from my device (if it is laptop, I must note whether it is battery powered or plugged-in because this often can change a screens intensity-for the field it is better to do this battery only) I can then rename this jpg with all of my settings, thus for example f4_50mm_+2oe_1/50s_1600iso. Thus anytime I need f4 for my 50mm lens I call it up on the digital device, stick it in front of the lens (with +2 dialed into the OE) and lock the exposure. Once I have made my tables (a matrix of greyscale images) this is very quick to do and most of all REPEATABLE. Since I know that I have chosen f4 and 1/50s, then the only variable is ISO which I can choose at will with the OE dial and which the liveview often gives a surprisingly good indication of the relative over or under exposure of a scene.

In the absence of being in manual control of your camera, control your light source! And then lock it in!

puredrifting
04-25-2009, 11:57 AM
I like this. I just got an iPod touch, I will have to try this. Have you been doing this workflow and it really works? So if I am using Nikons instead of Canon lenses, I would really only have to do this using each f stop and then get the camera to set the desired ISO and shutter speed, right? Would even be a bit easier?

Dan

yoclay
04-25-2009, 12:57 PM
Exactly right Dan. It works. I use almost only manual lenses. I find the iphone/touch a little small for big lenses. So I use a 8" digital photo frame (res 800 x 600) which seems to have even greater exposure range. But any of these kind of devices will work. My goal is 1/50 sec. and the only thing to remember is that outside with ND's it is better to have a swing away mattebox, otherwise you will have to have settings with the screw on ND filters as well. This is why in fact the wisest thing to do is to find the handful of settings which you use most commonly.

puredrifting
04-25-2009, 01:41 PM
Cool tips man, thanks. I will definitely have to try this when my 5D arrives.

Dan

dantewaters
04-25-2009, 09:28 PM
Wait the ipod touch is what a viewfinder?

puredrifting
04-25-2009, 09:44 PM
Read the fine print Dante...

"I always cover the lens entirely with the digital device."

He is suggesting using the screen of an iPhone or iPod touch or a digital photo frame to consistently display a calibrated gray scale screen. You would then use the camera meter to read the screen and consistently set the same ISO and shutter speed and aperture.

Dan

pressphotographer
04-25-2009, 10:16 PM
Ah, the swing away mattebox, genius! I wondered how you were coping with ND filters!

Dan