I have purchased the Canon 5D w/24-105L lens which I intend to use primarily for panoramic/multiple image shooting, all images to be stiched together in Photoshop. I am having a problem getting consistent images - images without subtle density variations or color shifts. I am shooting with manual focus, manual aperature, a preset white balance (I have been advised to create a custom white balance) and still in a set of five - seven images with generous overlap I am getting subtle variations - fixable in Photoshop, but enormously time consuming. The question is - should I expect the 5D to be able to produce consistent images without variation in "full manual mode" or will the sensor always produce subtle variation? Any thoughts much appreciated -

I don't think you will be having an issue with the exposure of the sensor - it is more likely some manipulation happening in software (camera for jpeg, raw conversion otherwise) after-the-fact. Layout your workflow in a bit more detail and maybe we can give some more suggestions.

I did have a similar problem doing pano's with my 10D - the problem was that I was taking so many images (upwards of 30) that the camera was just not coping trying to dump raw files to the CF - so I had a number of shots where many, many seconds elapsed between shots and the light was changing in the meantime (as it does at sunrise!).

Andrew

I would guess you might be running into issues with barrel/pincushion distortion and/or vignetting, both of which would make stitching photos difficult. The 24-105mm f/4 L IS is a well regarded lens, but it probably isn't the best lens in the world for stitching photos due to distortion/vignetting.

What software are you using to stitch the photos with? There are more powerful solutions out there than just using Photoshop.

Thanks for taking the time to respond - the workflow, as of now, is not too elaborate: I'm shooting to a 2 gig SanDisk Extreme III card, loading the card into a Lexar firewire card reader and using Image Capture to transfer the RAW files to a new folder on a hard drive. I then use iView to catalogue and view the images and then open the files into Photoshop (CS2) using iView. This opens Bridge, and so far I have just been open 4 to as many as 7 images ata a time in Bridge, slecting them all, and applying a very basic RAW conversion to all of the images which then open them in Photoshop.

I will then use Photomerge to line them up, then save them "as layers" out of Photomerge and which point they become a layered Photoshop file (TIFF or PSD) and then using layer masks, I stitch and blend. It's at this point that I have been noticing subtle changes in tone and density.

I realize that in production I must create custom while balances for what I am shooting, which I have not been doing yet.

Thanks a lot for taking a look at all this - john

I try to always have the zoom set at at least 50mm, if not longer.

I'm stitching in Photoshop as I like the control it gives me for color matching, masking, etc, etc. If there's a another program you'd recommend (MAC please), I'd really like to hear your recommendation - thanks for your time and Best - John

A 50mm f/1.4 or 85mm f/1.8 prime should have little distortion and almost no vignetting stopped down to around f/8, and both are relatively inexpensive... under $400. Just a thought.

I recently bought an EOS 5D and already own these two primes so I'll be trying it myself as soon as the rest of my pano parts show up from Really Right Stuff.

Another thought... if you're talking about custom white balances you must be shooting jpeg. Have you tried Autostitch? It's free, and it's results can be surprisingly good.

www.autostitch.net

John,
You may try Stitcher 5 or Stitcher Express. Michael wrote an article here about version 4.0. Demo versions are available for download at Real Viz website. Other alternatives are PTMac and PanoTools, you can get an idea of this softwre here. I don't have an extensive experience with either of these products

As for the difference in hue you need to use the same white balance on all your photos. Also make sure that your camera is in full manual mode (not the Av mode but the M mode). Don't use a polarizer filter.

Take 2 or 3 shots of one section of the pano before moving the camera and see how similar they are after processing. Obviously if the light is changing rapdily that's a different problem.

You didn't mention shutter so I assume you had that manually set too?

If it is an issue caused by the camera then I'd be suspect of the shutter more than the sensor. The 5D is not one of Canon's high-end cameras and so a not-so-precise shutter may have been used. The timing may vary between exposures and lead to those subtle brightness variations you noticed.

Durt, I have noticed the same thing sometimes. Your workflow does not seem to be the problem since you are getting Bridge to convert them the same way. When I've seen it, it's quite subtle, but when pixel-peeping on seams, you can see it. I have used Stitcher and it can do quite a good job equalizing images so these differences cannot be seen in final views/prints. It has a bizarre interface (compared to ones designed by Mac users as opposed to folks porting from somewhere else) but can do quite well. If the FL is relatively long (e.g. greater than 30mm in 35mm equiv terms, it autostitches well. Check out a demo.

My thought was related to the precision of the shutter. Changing light is always a problem, and many panos are shot at the time of day when it's changing quickly Hard to avoid that issue. You could check precision by taking several shots taken (when the light is reasonably steady) at the same shutterspeed - the one used when you noticed the problem - and seeing if they show similar variations. If it's set for e.g. 1/60 sec the exposure should be 0.016666 seconds. If the shutter's precision is specified as e.g. ±2% this would give a midtone (level 128) a range from say 125 to 130; is this the kind of range you are seeing?

Does anyone know if Canon specifies their shutter precision anywhere?

Andy

Andy -

Those are excellent suggestions and comments. I did some tests yesterday having removed a haze filter which I was using for element protection only but it had definitely created a mild vigneting that was adding to the problem.

The problem still persists, but now exactly along the lines you have described - very subtle, but problementic, upon closer examination usually entails both a density shift and a chromatic shift, usually along the cyan/red or magenta green axis. It's not predictable - i.e. of a six shot panorama, the third shot may be out or the fifth.

I spent several hours on the phone with Canon yesterday (yes, pray for me) - the only useful bit of information was an insistence that I use center weight metering instead of evaluative. I explained that I was shootin in full manual (shutter, aperature, custom white balance, etc) and the tech insisted that even in full manual the metering capacity of the camera is "sending impulses to the sensor" - can this possibly be true????

I have downloaded a trial version of Stiticher and - weird Euro interface aside - seems like an interesting program anad I will be exporing it more.

I do not have any info on the Canon shutter issue but will look into it.

I should add on top of all this that my EF 24-105 mm F4L lens is subject to recall - whether or not that's contributing to the problem, will advise.

thanks for your thoughts - durt

This particular problem brings to mind a question that I've had about ACR and Bridge processing. Using CS2, for RAW images, my ACR default setup is that all possible settings (exposure, white balance, etc.) are done automatically. If I select, say, five RAW images for a panorama, load them into ACR all at once and then synchronize them, to what setting are those images synchronized? It seems to me that each individual image setting remains on automatic. Even if I shoot each image on identical full manual camera settings, the auto ACR settings may still vary slightly from image to image. For this reason, I've been unchecking the auto setting for one particular image (usually one in the middle of the pano) and synchronizing all the other images to that one.

What is the recommended workflow?

They sync to the very first image in the series. As you noticed, if the first is set to Auto, all of the others will be in auto too and you'll get a whole-lotta nowhere.

What is ACR?

"Adobe Camera Raw"

Hi Durt,
Given that your lens is due for recall; (any lens under the number UT-1000 ;
Canon notice: We have recently discovered a problem with early production samples of the EF24-105mm f/4L IS USM lens in which flare occurs at an unacceptable level under certain conditions. The flare is most obvious in the wide zoom and wide aperture settings.) { This doesn't mean flare won't show up under the scrutiny which you are giving your stitching }
I would suspect that you should get a lens fix before judging the whole camera system.
I have had great success with Raw files and the same lens (later non recall version ) & camera. I have not seen any chromatic nor density shift. I have verified this with my 180 mm Macro lens on the 5D too! ( I shoot flowers mostly and I can tell you that the colour matches are exceptional )
I hope this is useful.
Regards,
Owen

Friends - Have completed a series of systems tests and experiments I have got the system working properly.

Manual Exposure
Manual Aperature
Custom While Balance frok 18% grey card in proper ligth
Generours overlap

Converting RAW files - Select all files and then synchronize them and them make sure that the settings have been applied to each image.

Open the images into CS2 and automerge them and save as layered file.

Use layer masks and a little bit of gradient tool and it just works, works, works.

I purchased Stitcher and that may have been a mistake - we will see.

thanks for all your help and suggestions - durt

Look, I'm no expert and I'm just guessing here, but...

The 5D is known for some light fall-off towards the edges of the image - two photos in your panorama will have a given part of the scene near the edge in one photo and near the center in another - you will expect a slight darkening in the first situation comapred to the second.

I'd suggest (as someone else did) using 50mm as a minimum focal length - if you can use longer, then do so. This will reduce the light fall-off problem to just about zero (as it's worse at shorter focal lengths), and has an added bonus of avoiding perspective distortion, making the images easier to line up.

Changes in actual light cannot be controlled, but perhaps using a longer lens will solve the avoidable problems.

I'm not sure if you correct for distortion, but if not, try PTLens. It's free and it works though I'm not sure if it is precise or just good enough. Leif

Put somewhere 2 RAW files (if you can) that make the biggest problem for you to stitch. I try stitch them in my workflow (PanoramaTools, PS CS2+ACR, Enblend) – if I was successful I give you exact instruction how I make this working….

Best regards
Yansen.