exposure issues using a DSLR as a lightmeter

[Greg Miller]

The other way round - the camera LCD is displaying a jpeg interpretation of the raw file. Generally I find my LCD displyas a brighter more contrasty image, which when opened in a raw converter turns into a flatter, slightly darker image

I keep referring back to this article: http://www.luminous-landscape.com/tu...aw-files.shtml

This is also helpful - http://forums.adobe.com/message/4698680 (a lot of the posts are chit-chat, but the linked pages are good)

Getting a little off-topic now, but if you want to modify the camera settings to give a more accurate preview then search for UniWB

http://www.malch.com/nikon/UniWB.html

http://www.luminous-landscape.com/fo...?topic=63997.0

and finally, for your camera - http://www.luminous-landscape.com/fo...?topic=59776.0

No. The jpg conversion is only going to compress the shadows and highlights. But will not make mid-tomes darker or brighter. It will only make the scene more contrasty (but not brighter or darker).

[Simon Liddiard]

No. The jpg conversion is only going to compress the shadows and highlights. But will not make mid-tomes darker or brighter. It will only make the scene more contrasty (but not brighter or darker).

You are probably correct. I think the slight alteration of the colour might lead me to perceive a darkening. The contrast is certainly altered.

[Greg Miller]

You are probably correct. I think the slight alteration of the colour might lead me to perceive a darkening. The contrast is certainly altered.

It's definitely correct. But it is irrelevant for this conversation anyway.

For most people shooting Velvia, the main concern is not blowing out highlight detail. Assuming 5 stops of exposure latitude, people generally will spot meter the highlight, then expose 1.5 to 2 stops stops under that. This keeps the highlights just below the point where they will blow out. And the mid-tones and shadows fall where they may. So Andrea needs to understand how to meter the highlights (this is where the spot meter mode comes in handy) with his DSLR, and then translate that to a proper exposure with his LF film (calibration testing).

[Simon Liddiard]

It's definitely correct. But it is irrelevant for this conversation anyway.

True. Just for clarity my comment about you being probably correct was only because I didn't have my camera to hand to verify myself, not because I doubted your information!

I found this article on calibrating a meter to a digital camera - http://www.frankdoorhof.com/site/201...e-quick-notes/

Is that pointing in the right direction?

[Andrea Gazzoni]

The screen shots all show using most of the dynamic range of the DSLR, which is way more dynamic range than Velvia can handle. It is entirely possible that the Velvia exposure was proper for holding highlight detail, but the contrastiness of Velvia pushed the mid-tones into deep shadow

...understand how to meter the highlights (this is where the spot meter mode comes in handy) with his DSLR, and then translate that to a proper exposure with his LF film (calibration testing)

I'm not sure this is a matter of dynamic range, Greg.
I've often shot the same type of scene, always in low light, with almost only midtones. In the past I was always using Velvia 100 and I did not have these problems.
In my limited knowledge, scenes like the one attached here below are not so challenging for Velvia, none the less the film shot came out almost black.
It seems more likely that it is an improper use of the dslr on my part, combined with a minimum loss of speed of the film.
I am going to do some more tests, most of all I will have my Pentax spotmeter calibrated.
thank you all for your advice

[Simon Liddiard]

It seems more likely that it is an improper use of the dslr on my part, combined with a minimum loss of speed of the film.
I am going to do some more tests, most of all I will have my Pentax spotmeter calibrated.
thank you all for your advice

Keep us posted man, good luck

[Greg Miller]

I'm not sure this is a matter of dynamic range, Greg.
I've often shot the same type of scene, always in low light, with almost only midtones. In the past I was always using Velvia 100 and I did not have these problems.
In my limited knowledge, scenes like the one attached here below are not so challenging for Velvia, none the less the film shot came out almost black.
It seems more likely that it is an improper use of the dslr on my part, combined with a minimum loss of speed of the film.
I am going to do some more tests, most of all I will have my Pentax spotmeter calibrated.
thank you all for your advice

I'm just commenting based on the histograms that you posted. I may be wrong, but I believe the 5D II has about 8 or more stops of usable dynamic range. Velvia has 5 stops. The histograms show information from the far left (deep shadows) to the far right with some clipping (its possible that you increased contrast in the RAW conversion or post processing but I'm assuming these are straight out of the camera). That would mean that there is significantly more dynamic range in those specific scenes than the 5 stops of exposure latitude that Velvia can capture. So if you use Velvia (or pretty much any other transparency film) with these specific scenes, you have to make a compromising decision. Protect the highlights which will cause the mid-tones and shadows to be rendered darker than when seen with the human eye (and which it sounds like actually happened). Or expose the mid-tones so that they appear normal brightness, but allow the highlights to be blown out.

[Ed Bray]

I'm a little surprised that no one has mentioned (I didn't check all the links in posts) that DSLRs are calibrated to give a 12% grey whilst a typical meter is calibrated to give 18% grey.

[Simon Liddiard]

This is all useful information!

[Kirk Gittings]

I'm a little surprised that no one has mentioned (I didn't check all the links in posts) that DSLRs are calibrated to give a 12% grey whilst a typical meter is calibrated to give 18% grey.

Not so important if you use the histogram and pay close attention to the highlight and shadow renderings plus take into account the dynamic range of your film vs. the DSLR rather than paying attention to the midtones.