EOS digital vs film exposure?

[DocFrankenstein]

Has anybody tried using the digital camera as "polaroid" for film stuff?

How close does it gets? Is it a good idea?

[gasrocks]

Do you mean as a test for correct exposure? Yes, settings (iso, shutter, f/) transfer. Also means you can use sunny f/16 rule with your digital camera.

[Bob_A]

Has anybody tried using the digital camera as "polaroid" for film stuff?

How close does it gets? Is it a good idea?

Thanks for the great idea! I'll have to try that.


Regards,


Bob

[mdr]

Great idea, now I can use my EOS 3 spot meter and transfer the settings to my 20D.

[slin100]

There is no guarantee that ISO 100 on a digital camera equates to ISO 100 on a film camera. That's because the standard for calibrating the meter on a film camera is based on achieving a specific film density. There is no such equivalent notion for digital cameras. In fact, the ISO standard (12232) for manufacturers to follow when calibrating meters allows for two different ways for setting ISO speed on digital camera. Unfortunately, you have to pay money to read the standard. :(

You can read this Kodak application note which is derived from the standard to see how Kodak does it.
http://www.kodak.com/global/plugins/acrobat/en/digital/ccd/applicationNotes/ISOMeasurements.pdf

There's a summary of the application note here, too:
http://www.normankoren.com/digital_cameras.html#ISOspeed

[Longwatcher]

I did try using my D60 or 10D as a meter for my Hassleblad a few times, before I stopped using my Hassleblad. It worked fairly well. What was really fun was trying to use the 10D to trip the flash at the same time as taking a shot with hasslebladwith a slow shutter. Got it to work 2 out of 7 attempts. I did this because the flashes were not compatably with my old Hassleblad.

[DocFrankenstein]

I think I need to take a course in optical physics to understand this stuff.

[Jon]

Which stuff? Using the digital camera to verify exposure before shooting film, you'd just need to calibrate the dSLR so you know which settings most closely match the ISO, contrast, saturation and latitude of the film you're using it against. No optics - just a lot of test shooting under controlled conditions.

Using it for framing/DoF/composition, you're going to have to deal with the (oh, no, he's going to say it - women and children and CDS to the lifeboats!) crop factor - there an understanding of optics may help, but a full-frame dSLR would help more.

[PacAce]

There is no guarantee that ISO 100 on a digital camera equates to ISO 100 on a film camera. That's because the standard for calibrating the meter on a film camera is based on achieving a specific film density. There is no such equivalent notion for digital cameras. In fact, the ISO standard (12232) for manufacturers to follow when calibrating meters allows for two different ways for setting ISO speed on digital camera. Unfortunately, you have to pay money to read the standard. :(

You can read this Kodak application note which is derived from the standard to see how Kodak does it.
http://www.kodak.com/global/plugins/acrobat/en/digital/ccd/applicationNotes/ISOMeasurements.pdf

There's a summary of the application note here, too:
http://www.normankoren.com/digital_cameras.html#ISOspeed
If you buy a Sekonic L-358 or L-558, you can use it to set the expose on the EOS Elan, which is a film camera. You can also use it to set the exposure on your EOS 20D which is a digital camera. Now, as far as I know, there is no switch on ther Sekonic light meters that allow you to select the type of camera you are using such as "film" or "digital". So, one would think that it would be logical to assume that you can use the 20D to set the exposure of a film camera as well, no? Or am I missing something? :)

[wilflee]

I've been doing this for a while now. Using the Powershot G1 as polaroid. It actually performs better than polaroid as far as shadow detail and contrast range is concerned.

However, slin100 is quite right in that ISO200 on the G1 isn't exactly the same as PKL or EPD. One can't expect the CCD to react to light the same way as emulsion, especially when shadows & highlights blow out of the range of the CCD. No computer monitor I know of can display that range of contrast either. The relative color interpretation between CCD & film also don't behave the same way - if you get the blue to match, then the red looks off, etc.

In the end, keep in mind that a polaroid is just to give you a quick snapshot of the shapes, relative sizes, perspective and shadow/highlight location of the final print. The real computer that determines correct exposure/lighting is still the one between the photographer's ears.

[Huckaback Photo]

Pac Ace

Your not missing anything in fact your spot on in my view.
We run a shop called Huckaback and specialise in period linen, so its most important to get the whites right.
for me whether using the 1D mk 2. or D 60......medium format...........35mm there is only one real answer if its studio flash or available light I use my old trusty Gossen Lunasix F
and set up whichever camera accordingly.
if it meters the flash at f11 it will be f11 on all cameras.
the big advantage of the digital is conect to the laptop and I know what the film cameras will produce before developing, vary usefull.

Please check out the accuracy in the whites metered as mentioned above by looking at my image , click the original quallity to see whats possible from a standard 50mm f1.8 mk 1 lens at f11. this picture has been used in our adverts and has one several competitions for me.

Martin (Huckaback Photo)

click under the picture to view the original size

http://www.pbase.com/huckaback_photo/image/40070989

[Huckaback Photo]

Just thought
I actually own a polaroid back for my medium format cameras and canot remember the last time I used it, I recon its so much easier and cheaper with digital for test shots, also I use manual settings not auto.
Martin (Huckaback Photo)

[slin100]

If you buy a Sekonic L-358 or L-558, you can use it to set the expose on the EOS Elan, which is a film camera. You can also use it to set the exposure on your EOS 20D which is a digital camera. Now, as far as I know, there is no switch on ther Sekonic light meters that allow you to select the type of camera you are using such as "film" or "digital". So, one would think that it would be logical to assume that you can use the 20D to set the exposure of a film camera as well, no? Or am I missing something? :)
Does the metered exposure from the Sekonic match that of the 20D? I happen to have a L-358 and it doesn't match the readings I get from my 10D.

I haven't done a scientific test to quantify the difference because I usually only use my Sekonic to measure lighting ratios in the studio. Even if I did do the test, it still wouldn't tell me the cause of the difference. For all I know, the meter on my 10D could be miscalibrated (unlikely because I seem to get good exposures most of the time). Or the T-stop of my lens could be factor. Finally, the ISO rating set by Canon could be different. This is my main point.

To answer your question, you've only considered the calibration of the meter. It doesn't address the response of the sensor and, more importantly, where Canon's engineers decided to put the metered middle-gray in the image data.

[slin100]

Please check out the accuracy in the whites metered as mentioned above by looking at my image , click the original quallity to see whats possible from a standard 50mm f1.8 mk 1 lens at f11. this picture has been used in our adverts and has one several competitions for me.

Martin (Huckaback Photo)

click under the picture to view the original size

http://www.pbase.com/huckaback_photo/image/40070989
Martin,

Excellent shot, but accuracy of the whites has more to do with white balance than it does with exposure sensitivity.

One can validate the manufacturer's ISO rating against the sunny 16 rule. Take two exposures: one using the camera's metered exposure, and one using the sunny 16 rule. Which exposure produces a more faithful image? I don't have my 10D with me but I seem to recall that its meter is about 1 stop off of the rule.

There are plenty of reports on the Web about how the ISO ratings on digital cameras are not accurate. My old Canon G1 was reported to have a rating closer to ISO 80 when set to ISO 50. That probably explains why I regularly blew the highlights with that camera. :)

Here's one review that claims that the ISO 100 on a Canon A80 is closer to ISO 200 on a 10D.
http://www.photo.net/equipment/canon/a80/

[Huckaback Photo]

Stevan
sorry I had intended to say Detail in the whites not accuracy in the whites,
as its the sensitivity were dealing with.
The other point is I'm not talking of usinga digital camera to get the exposure settings, I actually use a hand held meter/ flash meter and camera on manual.
So if the studio flash metered f 11 and say I had 4 different cameras set up in a blacked out room I could set all to bulb and f11 on each lens all shots should be the same (fingers crossed)
Of course I have to agree with you there will always be variables in dif cameras.
who can say the apperture closes to exactly same size on each lens or the shutter speed at 1/30th is actually running at 1/20th using the manual mode.
Auto of course is different .
if we set a speed calculated by the hand held meter, its that shutter speed we expect the camera to give us.
reminds me of years ago I had all 3 of my Olympus bodys tested by a camera technician for shutter acurracy my OM 4 was amazingly spot on through the range the 1, OM 2 was fine down to about 1/15th but other was out by half a stop.
If only all in this world was perfect ...we should have nothing to complain about.

I think the one great thing about digital is the amount of adjustment with post processing.
unless of course the whites are to blown out, then we struggle.

Cheers
Martin (Huckaback Photo)

[Jon]

Differences in ISO ratings between film and digital are as likely, or more likely, to be due to the photographer's preference in exposing the film, or inaccuracies in the shutter speeds or aperture openings, or deviations in the calibrations of the individual meters than they are to any particular differences in digital vs. film ISO. If you use a separate meter for your exposure, you'd need to calibrate it to your particular camera regardless of whether it's a film camera or a digital. And you'd need to calibrate it to every camera you used it with.

[primoz]

Hehe or you can just sell EOS 3 and get any decent Sekonic or Gossen light metter for that money, which does job far better then any in-camera light meter :) Not to mention it's smaller, lighter and easier to use :)

[Phil V]

Sorry to have to state the obvious here but:
How many of you guys used different films over a period of years?
The ISO standard is a line in the sand, manufacturers have made film based on it, camera manufacturers have built meters around it, and now digital sensors.

But for years pro's have been rating their ISO100 slide film at 80 (for a bit of extra punch) or their ISO160 portrait film differently, not to mention all the complexities performed with B&W neg film by people trying to create that perfect image (in their opinion!).

The ISO standard is a standard 'designed' for film, however anyone who believes that digital sensors aren't designed around it are just confusing themselves and anyone else who will listen. It's a line in the sand camera manufacturers have been working to ever since they put meters inside cameras. But guess what - they never always agreed what a 'correct' exposure was, and their users didn't always agree with what they'd come up with. This isn't a digital phenomenon, it's a debate almost as old as photography.

As for colour balance and it's relativity to exposure, YES we had that with film stock as well. Believe it or not, different films treat different colour values differently, just like different sensors and different processing chips and RAW file types.

[nat869]

I have been planning to do this very thing. I bought a medium format camera and I figured if my histogram is "exposed to the right" and is pleasing to my eye then that same setting should be pretty close for film. I should get my chance to try soon.

[DocFrankenstein]

So, phil... Should I just shut up and use my light meter? And then just adjust plus/minus haft a stop later with experience?

[KevC]

I think I need to take a course in optical physics to understand this stuff.

Hehe. PHY255F: Oscillations and Waves. I'm taking that next year.

Anyway, good thread! I'm interested, because I'm getting an old SLR soon and have high doubts that the lightmeter will work.

[Huckaback Photo]

Phil
wonderfully said I agree totally. also been there done that..slide film at 80 iso normally worked a treat, just that extra bit of saturation to.
a lot of this is getting to know your kit and how it responds to various conditions,
often people take for granted what a camera metering system tells them is the right exposure, to be honest some of todays cameras are so good that 90% ( just a guess) of the time its spot on.

A good light meter will teach you to understand light in all its forms, Reflected or incident readings. Flash/Daylight. high key/ lowkey. Fill flash/ Contre jour. Lighting ratio in the studio and much more.
The point you made about not always agreeing with what was correct exposure is vary important as you soon got to learn that some subjects needed more ex and some needed less exposure,
so get to know your own individual system and what works best for you.

in my darkroom days of Black & White dev & printing, to start the ISO would be set to suit developer and sometimes pushed or pulled according to subject matter.
For anyone not got a meter Why not try one you may be supprised. if using studio flash it a must, and where would the wedding photographer be with out one..1 to 4 fill flash incident reading set
f stop and set flash 2 stops wider to suit etc.
lots of uses.

Martin (Huckaback Photo)