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ExpoDisc vs LCC for lens calibration and white balance

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Stuart Richardson

Active member
Hello, I was wondering if you guys had any experience here. I am looking for something to use for white balance and creating white shading files for my Sinar back. I am curious if anyone knows which would work better, an expodisc or an LCC like Capture Integration sells?

I am not sure if one or both are shoot-through, or is the LCC meant to be reflective? I believe you are supposed to shoot a flat white surface for the Sinar white shading files, but I imagine it would work with an evenly lit opaque filter as well...

Ideally it would be able to make white shading files, and then function as a white balance tool in the field...
 
T

thomas

New member
Stuart Richardson said:
Ideally it would be able to make white shading files, and then function as a white balance tool in the field...
Click to expand...
as for white balance I'd assume it's not a big difference. regarding white shading I see the lenses on the front of the expo-disk critical (though there is a matte screen behind them). Too, some vignetting could be introduced. Just my thoughts... never tried the expo disk.
The LCC plate works very well (yes, shoot through). However I often use a grey card reflecting the light in the scene as well for WB.
 
E

ericstaud

Guest
Stuart Richardson said:
Hello, I was wondering if you guys had any experience here. I am looking for something to use for white balance and creating white shading files for my Sinar back. I am curious if anyone knows which would work better, an expodisc or an LCC like Capture Integration sells?

I am not sure if one or both are shoot-through, or is the LCC meant to be reflective? I believe you are supposed to shoot a flat white surface for the Sinar white shading files, but I imagine it would work with an evenly lit opaque filter as well...

Ideally it would be able to make white shading files, and then function as a white balance tool in the field...
Click to expand...
Both the white plexi and the Expodisc work fine for Shading/LCC and also for white balance. The Expodisc can give some vignetting if not big enough. The Capture integration version is the way to go for price. Before that one was available I bought the Expodisc because it had a strap I could hang from my neck or the tripod. The plex that comes with Phase one cameras is about 5"x7" and I didn't want to cut it down or drill a hole to put my own strap on it.


These things work great for white balance, but you have to turn the camera to the light source.
 
etrump

etrump

Well-known member
I use the small LCC card that CI sells. I tested several scenes using both LCC and Expo and they were usually within 50 degrees of each other.

Like Thomas, I find shooting a gray card in the scene for WB reference is more accurate in scenes that have a lot of the same color. Shooting the LCC card gives you an average of the reflected light of the scene while the gray card gives you the temp of the ambient light. Having both takes an extra image but sometimes one is better than the other.

For instance, this image had so much green it threw off the LCC calibration. The temp was right but the green/megenta slider was removing too much green so the water had a slight megenta cast. I shot a gray card and the color cast was much closer.

 
Bob

Bob

Administrator
Staff member
the lcc plate works very well for lcc, but white balance is better with a card designed to te purpose, The problem is that if you are in an area of filtered daylight, you might not want that as your white balance eference. For most landscapes, just set the back to daylight or cloudy as appropriate, then just tweak a bit to taste. This is better than a cast that might be caused by filtered light on your white balance card.
-bob
 
S

Stuart Richardson

Active member
Thanks Bob -- but my back has strange white balance issues -- just setting it to daylight or cloudy does not really work. This is why I am looking into another solution.

I need to do LCC anyway, so the card is probably a good bet. I have a regular grey card I will try for white balance....I just never remember to bring it in the field.

Ed, Eric and Thomas -- do any of you have the measurements on the pocket LCC plate? I am just curious because come of the Rollei lenses are quite big -- the 180mm and 110mm are 93mm filters...they are less in need of calibration though I guess...
 
B

bdp

Member
For lens casts you should be using the proper Sinar part or similar:



Part number 551.43.098. Its a two-layer plexi sheet 100mm x 100mm. Then correct with the shading mode in eXposure after you import you pics.

As far as WB goes, I just tweak to taste during processing, or get an assistant to hold a white or grey card in the shot and do a manual WB in the back during shooting. I find shooting a proper 24-square colorchecker under the lighting at the shoot and then making a custom calibration during processing is the most accurate way to do it, but often a hassle, so I just try some previous ones in my library during processing and choose the one which renders the colors to my liking the most.
 
carstenw

carstenw

Active member
bdp, having a Contax 645 and Sinar back, which EXIF fields are automatically filled in, when you use a Contax lens?
 
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bdp

Member
Aperture and exposure time and mode (M, Av, Tv etc). No lens focal length or distance - I believe the Hy6 can give this info. You also get all the info from the back of course - ISO, WB etc

Ben
 
S

Stuart Richardson

Active member
Thanks bdp -- that is very useful. I will see if I can find the Sinar part, but I am not holding out too much hope. Their parts always seem to be hard to find, special order, and very expensive. I think the color checker is a good way to go too. If I want to be sure that I am getting the real colors, I think custom calibration is probably the only way to get it right. I might even be able to find one here in Iceland.
Also, thanks for your response in the thread on the LCC/white sheet awhile ago. I just found it now, and it looks like it will be a very easy step by step for when I get around to making the white shading files.
 
S

Stuart Richardson

Active member
Hi Ben,
We do not have a Sinar dealer here in Iceland. The closest would be Denmark or the UK. I am from the US and bought my camera from Calumet. The price on the US price list is $125. I would have to add to this maybe 30 dollars shipping, a 2000kr customs fee and 25% tax on everything. This would leave me paying $212 USD for a piece of plastic. I just bought a Nikon 35mm f/2 lens for 220 USD. You can't slip by customs in Iceland -- it is a small country so they intercept every single package and you need to show a receipt and pay 24.5% tax or they will not release the package. The Capture Integration one is 17.95, and I can probably get someone to bring it with them on the plane when they visit me (admittedly, I could do that with Sinar too, assuming they have it in stock).
 
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bdp

Member
In that case I'd go for the Capture Integration one. You could even make one out of two sheets of opaque white plexi, a spacer and some superglue! But seriously, this is one area where it wouldn't hurt to save some money and get a generic accessory. Capture Integration only sell top notch gear from what I can tell. It doesn't look like it would make any difference.

Ben
 
B

bdp

Member
Here is the Sinar metadata info. Interesting how the Phase shows the focal length, but the Sinar doesn't, and the Sinar shows the exposure program but the Phase doesn't! Obviously both sets of info are available from the body to the back, but each brand chooses to ignore one piece of info each.
 
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S

Stuart Richardson

Active member
Yes, I think that's the case too. I am willing to pay for something when it is unique and a good value, but for this sort of thing I don't think it makes sense to pay a huge premium just because of the label. I am sure the Sinar one works brilliantly, but it probably costs them 2¢ to make. As long as the plastic piece is totally uniform in color and texture, I would assume that the calibration process itself would neutralize any particular color cast or difference. When I originally talked to Sinar a few months ago, they said any uniform white card would work, though the shoot-through plastic plexiglass ones worked best because they were easiest to get uniformly lit.

But anyway, thank you very much for the help! It's good to have some advice from someone who has done this before with Sinar equipment and software. If I have any problems, at least I know someone has done it before....
 
carstenw

carstenw

Active member
I find it a bit frustrating that the lens is not indicated, but then again, I use that piece of information so rarely, and in any case my lenses are spaced far enough apart that I could probably just look at the image to see which lens I used.
 
carstenw

carstenw

Active member
I have some questions about Sinar backs that I have no clue how to answer:

- What if I buy a Sinar back, but Sinar goes out of business. Are there places which repair such backs?

- Does anyone have experience with insurance claims on a broken back with no support

- How often do backs fail?

I am leaning towards buying the back in any case, but I would like to have clearly in my mind what the consequences are if it fails. The situation would be quite similar to buying a Kodak 645 Pro, I think.
 
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