Philadd Loc: Phoenix, AZ

Any of you canon users using an expodisc with your 24-70 mark ii? I'm thinking I'd like to get one but they only come in 77mm and my lens is 82mm. Thought about using step down ring but I'm not sure if this would affect the reading or not.

ecobin Loc: Paoli, PA

A step down ring won't affect the reading. I bought a $3 piece of foam board (1/4" thick) and cut a hole for the Expodisc -works great.

Philadd Loc: Phoenix, AZ

Thanks

sueyeisert Loc: New Jersey

I never used a step down ring try without one. I went from 72 to 77 had no problem.

abc1234 Loc: Elk Grove Village, Illinois

Try holding it centered on the lens. You will have vignetting but it will not interfere with setting the white balance.

Gene51 Loc: Yonkers, NY, now in LSD (LowerSlowerDelaware)

Use an Xrite Color Checker Passport - it is more accurate in a wider variety of lighting conditions - way better in non-continuous spectrum lighting. And more convenient to use, especially if you are shooting raw images.

sueyeisert Loc: New Jersey

Get it right in camera less editing

Gene51 Loc: Yonkers, NY, now in LSD (LowerSlowerDelaware)

That's exactly why you would use an Xrite Color Checker Passport - if you are not familiar, check them out -

abc1234 Loc: Elk Grove Village, Illinois

Gene, I have checked out the product several times on the website and while it appears to be a good product, I do not think it is better than Expodisc. Here are a few reservations and feel free to correct me on them.

It is fine so long as you have a subject standing in the shoot's lighting and is holding the Checker. What do you do for landscapes, street shoots, night scenes or sports?

Once you have your reference shot, you have to set all the other session shots to it in LR. With Expodisc, calibrate and shoot away. Both products are good as long as the lighting does not change. Both manufacturers mention this.

Talking about changing lighting, you create Checker profiles for your various bodies and apply them so long as the lighting does not change. How can you tell if the color temperature changes 250 degrees, enough to throw off your calibration without your eye noticing? To check this, you need a color temperature meter or recalibrate Checker.

All things considered, I will stick to my Expodisc and avoid any of the cheap imitations.

Gene51 Loc: Yonkers, NY, now in LSD (LowerSlowerDelaware)

It doesn't sound like you've actually used one.

I've used white cards, gray cards (Kodak 18%), Expodisk and Color Checker Passport, and I also used Spectracolor and Minolta color meters. All do the same thing - measure the color of the light falling on the subject. The color meters are out for me, because they proved finicky and unreliable, constantly requiring recalibration.

The gray and white cards change over time, and are not great with non-continuous spectrum lighting. Try shooting at night under a streetlamp.

I used the Expodisk for about a year, and was generally satisfied with it. But, I could not use it with my long lenses (300, 400, and 600mm lenses).

So I searched for a solution and found the CCP. The beauty of this approach is that you shoot raw and apply the profile later, in post, but it has a series of warming and cooling targets to make small adjustments.

Why I prefer it to the expodisk? With an expodisk you have to walk over to your subject's position, place it on the lens, point it at the light and create a custom white balance setting. That is a big pain in the tail when you have changing light, or settings that have mixed lighting in different levels. Much easier to not bother with creating multiple custom white balance settings and constantly changing them. I have shot in venues that had window light, stage light, and room light - all different colors and depending where you stood in the room the mix changed. Very challenging to do with CWB in camera. Way easier to manage with several profiles that are applied in post.

As far as shooting the target vs shooting the light to create a CWB - both are a pain. But you save lots of time by simply shooting a target, than having to stop what you are doing, install the expodisk, walk over to the subject, and point and create a CWB -

Night scenes - no contest - shoot the target, take your shots, apply profile, make creative adjustments, done.

Sports - hard to do with both - you either have to put the target in the same light as the subject, or you have to walk to the field and shoot the light with the expodisk. Same difference.

Changing light - already covered above. CCP way more convenient than making CWB for each condition.

Landscapes - its a draw - both work equally well. I still like the convenience of just shooting a target and not having to fiddle with camera wb settings.

I do find that color casts are better addressed with the CCP. the green-magenta spectrum sometimes is not accurately captured and corrected for with the expodisk. And I don't need to pick the standard or "warm-complimentary to skin tone version - the CCP covers that in their calibration target.

Only downside, if you can call it that - is that the color patches do drift in color value over time. So you have to periodically replace it - it does have an expiration date. I didn't have my expodisk long enough to see if the color drifted on it.

Anyway, my experience is that I get more accuracy, with less bother with the CCP than I did with the expodisk. I shoot raw exclusively. if I were shooting jpg, I would likely use the expodisk.

abc1234 Loc: Elk Grove Village, Illinois

Gene, thank you for your detailed and thoughtful response. You are right on the first point. I have never used CCP because having studied their website, I did not think it was any better overall than Expodisc. We generally agree on most issues.

What do you mean by non-continuous spectrum lighting? Is that lighting from different sources? Non-continuous would mean the spectrum of light from burning a single chemical element. But most of the lighting I am familiar with is a mix of sources that basically generates a continuous visible spectrum. From a photographic standpoint, it would not matter. In any event, shooting mixed lighting is a problem with either tool. A few steps here or there or following a subject as it goes from one kind of lighting to another wreaks havoc with any method.

I do not use the Expodisc as you describe. I always use it pointed to the subject thereby measuring the reflected light. The manufacturer specifies either direct or reflected measurement. This eliminates the inconvenience you describe. As for CCP's warm or cool variations, Expodisc comes in those flavors or you can change that easily enough in post-processing. However, doing so is a matter of interpretation rather than accuracy and you do not need CCP or Expodisc for these arbitrary changes.

How do you address this concern? The CCP targets are relatively small. That either limits the camera-to-subject distance or requires zooming in on the target. Is this of any practical significance? Another issue: how do you use all those color patches?

Gene51 Loc: Yonkers, NY, now in LSD (LowerSlowerDelaware)

Think of non-continuous as light that is emitted through a gas that absorbs parts of the spectra while passing the other parts - a rainbow in sunlight displays as continuous spectrum. Now imagine if pieces of the yellow, red, violet etc are missing - blank. Fluorescent, HID, Sodium Vapor, Mercury Vapor, etc are all non-continuous spectrum. The CCP excels with this type of light like no other system I have used.

Here is an interesting read, somewhat tangential to the discussion, but it shows the accuracy that can be achieved. Sometimes the result is subtle other times not as much.

http://www.dyxum.com/dforum/getting-the-color-right-part-1_topic103313.html

The problem with pointing the expodisk at the subject is that if you are looking at a scene with 80% green and there is a fair skinned subject in a red blouse, everything will have a magena color cast unless you include a color-neutral element in the scene and only read the light reflected from it.

I always got reasonably accurate color using the expodisk as an incident device. I never tried using it as a reflected measuring device - it made no sense to me - I could just as easily use the camera and no expodisk and get the same results.

When I shoot flowers - I place the ccp on the ground or in the foliage, where it receives the same light as the flowers. Take a shot of the target. Then continue to shoot until I move or the light changes. Just after dawn the color temperature and color casts are changing rapidly - I will shoot a target every 10 or 15 mins.

When I get to my computer. I look at each of my target shots, and use the "export to color checker" in LR to create the dng file and corresponding profile. I then attach the profile to the series of images taken after that profile, until I reach the next profile in the sequence, when I use the next profile and so on. it is impossible to mix them up, and if I do, easy enough to correct.

Doing the same wtih expodisk I have to stop, install the device on my lens, either point the camera at the light or at a gray card and create a cwb. When the light changes I repeat. It does take more time, no matter how you do it, to use the expodisk.

Using an expodisk to measure the reflected color of an entire scene is not all that different than using average white balance in camera, except that the camera's awb is only accurate from around 2800k to 5500k. Outside that range the results are inconsistent. I am not sure that (though I have not tried it) an expodisk pointed at the subject will provide the same accuracy as when it is used as an incident device. In situations like this, using software awb in post (Lightroom or PS or other applications) may provide similar results in most circumstances. Again, I haven't tested it - and probably won't since I already use the ccp.

abc1234 Loc: Elk Grove Village, Illinois

I think we are both chewing off more than we wish in this thread and we are starting to count the number of angels on the head of a pin.

Non-continuous spectrum. I do not agree at all. The only gas that matters to the photographer is air which is really a mixture of gasses. Air does not absorb light. High levels of water vapor and sols such as of sulfuric acid will disperse the light and changing temperatures will make it twinkle. Your examples are all of elements that do not emit light at all wavelengths and may be thought of as being non-continuous.

As for your example of 80% grass, I have worried about that too. Regardless of the explanation, Expodisc will still render the whites as white. No color cast. Perhaps I am being lucky but if this were a problem, I would have chucked the Expodisc a long time ago.

I do not know how fast you use the CCP but for me, the slowest part of the process is finding in which pocket I put it. I am done in under thirty seconds. As for LR, I balance the test frame, check it against the first shot and am done in fifteen seconds. From then on, I rarely ever have to change the color balance.

I am not saying Expodisc is the best product out there but merely want to clarify the differences between the two products so others can decide which one to try.

Thanks for the lively discussion. I will read the reference later.

Gene51 Loc: Yonkers, NY, now in LSD (LowerSlowerDelaware)

I learned about non-continuous light sources back in high school :)
http://www.light-measurement.com/spectra/

As far as convenience and workflow disruption, I am not alone:

http://www.ronmartblog.com/2010/12/using-x-rite-colorchecker-passport-in.html

Bottom line -

Expodisc does a decent job - though it can produce erroneous results, especially when used to measure reflected light. But if used as it was intended, as an incident device, it is more accurate.

It is the best way I know of to get accurate white balance if you shoot jpg.

It cannot be used with lenses larger than the size of the disk - if you use a 14-24 24-70 with OS, F2.8, Sigma 12-300 F2.8, Sigma 100-300 F4, 300mm F2.8 or longer lens - unless you can get the right size step down ring. In the case of the 14-24 there is no solution. There are too many lenses that cannot be used with an Expodisc.

CCP offers near 100% reliability, consistent results, fine tuning using the warming and cooling color patches (which vary both color and white balance simultaneously), and you only need to buy one to get white balance with anything from a Nikon 14-24 to a 600mm or 800mm lens.

Only downside is that it must be replaced every two years to ensure accuracy.

Each has pluses and minuses - but the CCP is more flexible and there is no disruption to workflow. I have used both - I see no benefit , given the way I shoot (raw) with the gear I use (numerous lenses with front elements larger than 77mm), to ever go back to using an Expodisc.

I wish you had tried both - as it stands, you have no real basis for comparison. You have the Expodisc, it works for you, you are happy, but you cannot really comment or compare one method with the other.

abc1234 Loc: Elk Grove Village, Illinois

I did read these two links plus http://www.dyxum.com/dforum/getting-the-color-right-part-1_topic103313.html. Except for the very relevant point of "1.1 Beautiful is not the same as exactly right" none of the articles offered much new to me. As far as I can see, the only real advantage of CCP is the color profiling that may reproduce certain colors better under certain circumstances.

I still fail to see how CCP is easier in the post-processing workflow. With Expodisc, you have set the white balance in the camera and do not have to touch it later. All the things I have seen on CCP say you set the color calibration in LR. No matter how you slice it, this is an extra step: first shoot CCP and then calibrate in LR.

As for the size issue, if that really matters, buy the 4x5 Expodisc. You can use the round Expodisc on a larger lens if you prevent light from leaking in.

While I am certainly open to trying CCP, due to limited time and the fear of the dreading gear creep, your very detailed discussion plus what I have read on the Internet have not convinced me that this is a must-have replacement for my Expodisc. If I every lose it, then I will start all over and try CCP. Please understand that my comments are not an analysis of CCP's use and results but rather my determining if I want to try it.