Rebel XT Long Exposure Processing...

[Brian Emfinger]

I dont know if anyone else has found this out but I thought I would share...

I found (while shooting the perseid meteors this last week) that if you are doing long exposure you can turn your camera off with the shutter still open and it will still save the picture..then you can turn it back on and shoot immediately. I only did this with 3-5 minute exposure so who knows if it works for longer exposure but the main thing is not waiting that same 3-5 minutes for the picture to process! It only works if you still have the shutter open when you turn the camera off.

 

[Darin Brunin]

I assume you're talking about if you have the long exposure noise reduction function on? Otherwise it processes the images right away for me no matter how long the exposure is. I think Canon must have made a software upgrade for the body because I think older Rebel XT's might have the problem you are talking about with any exposures longer than 30 seconds.

 

[Dick McGowan]

My XT used to take forever when doing long exposures (90 sec exposure would take 90 secs), I thought because of the camera, but I believe it must have been the CF card.
Anyways, this fixed it.

http://web.canon.jp/imaging/eosdigital2/e3kr2_firmware-e.html

If you go to your menu on the xt, it should tell you the version of firmware. Anything other than version 1.0.3 should probably be updated.

Key updates corrected...

This firmware update incorporates the following improvements:

1. Fixes the phenomenon of shots being unable to be taken when using the remote controller RC-1.
2. Fixes the phenomenon wherein the camera continues to scroll through images being played back.
3. Improves reliability in communication when using some CF cards.

And if you have version 1.0.1 it will also fix this

Q: Are the previous versions of the firmware included in this version? A: Yes, the following improvements from the previous version are included. Version 1.0.2 changes:

1. Fixes the phenomenon of extreme underexposure when using some lenses.
2. Fixes the phenomenon of auto power off function failure when auto power off is set more than 2 minutes.
3. Fixes the phenomenon of incorrect white balance when using an external flash.

 

[Gene Moore]

I dont know if anyone else has found this out but I thought I would share...

I found (while shooting the perseid meteors this last week) that if you are doing long exposure you can turn your camera off with the shutter still open and it will still save the picture..then you can turn it back on and shoot immediately. I only did this with 3-5 minute exposure so who knows if it works for longer exposure but the main thing is not waiting that same 3-5 minutes for the picture to process! It only works if you still have the shutter open when you turn the camera off.

You lost me on this one, what exactly is the point in doing this, to short cut the process time for noise reduction? If so, are you sure the proper noise reduction is getting done?

On my XTi 400d I have firmware 1:0:4 and I use either the Lexar 80X write accelerated CF card, or my new SanDisk Extreme IV CF card (very fast). Just now with the Extreme IV card I did a 20 second exposure with noise reduction turned on. The camera took the 20 second shot then flashed "Busy" in the viewfinder. In another 20 seconds the image (of my foot) appeared on the screen. Now, are you guys saying something is wrong here and I should not have to wait that extra 20 seconds?

Gene Moore

 

[Jayson Prentice]

No Gene, your camera is doing it just right. The reason the camera will take the extra time at the end of your picture is because you have the noise reduction on; so a 30 second exposure will take another 30 seconds of processing. You can turn noise reduction off, thus skipping that extra post-processing and it will only take a second or less before you can take another picture. I personally just have noise reduction off, beings most of the time on long exposures you should be using ISO 100 and your noise will be minimal.

In some of the XT's before an upgrade was made it seems like the noise reduction was always on and thus seemingly taking forever to write to the CF card. Like Dick said just update the firmware and any problems should go away...

 

[Brian Emfinger]

You lost me on this one, what exactly is the point in doing this, to short cut the process time for noise reduction? If so, are you sure the proper noise reduction is getting done?

On my XTi 400d I have firmware 1:0:4 and I use either the Lexar 80X write accelerated CF card, or my new SanDisk Extreme IV CF card (very fast). Just now with the Extreme IV card I did a 20 second exposure with noise reduction turned on. The camera took the 20 second shot then flashed "Busy" in the viewfinder. In another 20 seconds the image (of my foot) appeared on the screen. Now, are you guys saying something is wrong here and I should not have to wait that extra 20 seconds?

Gene Moore

Yeah it was processed and looked exactly the same as the others (and no I guess I cant explain why =)..and I havent tried it for longer exposures where it would be more usefull. I do have that latest firmware update but I always have on the noise reduction (I shoot a lot at night so I dont want to be doing that myself maunally) so I am guessing thats the difference in why mine takes a while to process while some dont.

 

[Gene Moore]

Yeah it was processed and looked exactly the same as the others (and no I guess I cant explain why =)..and I havent tried it for longer exposures where it would be more usefull. I do have that latest firmware update but I always have on the noise reduction (I shoot a lot at night so I dont want to be doing that myself maunally) so I am guessing thats the difference in why mine takes a while to process while some dont.

Ok, thanks .....I thought mine was working per the manual's instructions. Problem is, with some subjects like the meteor shower I don't want to lose 50 percent of my "shutter open" time waiting for noise processing. I could have easily missed my best meteor shot the other night. Likewise, some storms need full attention and we don't have the luxury of waiting that extra time....like a tornado in the lightning. I used noise reduction on some of the less severe storms last spring and it seem to be fine. I also used it on some of my daylight lightning shots that had long exposure times.

Gene Moore

 

[Jayson Prentice]

I have a question for some of you that are using the noise reduction. Are you guys seeing a significant difference in when you do and don't use it during long exposures? I've thrown it on a couple of times, but to me it just doesn't seem like it making much of a difference when I'm shooting ISO 100. I'm sure if you were using a higher ISO then it would be of help, but not sure why you would need that in long exposures.

 

[Brian Emfinger]

I have a question for some of you that are using the noise reduction. Are you guys seeing a significant difference in when you do and don't use it during long exposures? I've thrown it on a couple of times, but to me it just doesn't seem like it making much of a difference when I'm shooting ISO 100. I'm sure if you were using a higher ISO then it would be of help, but not sure why you would need that in long exposures.

Well at night (at least non-lightning related) I am always using 800 or 1600 but ususally 800. The one time I had the noise reduction off there were a million red dots and the noise reduction (through programs that have been recommended here) didnt work at all. I guess it helps being in an extremely dark sky area so doing 800 or 1600 looks awesome.

 

[Gene Moore]

Well at night (at least non-lightning related) I am always using 800 or 1600 but ususally 800. The one time I had the noise reduction off there were a million red dots and the noise reduction (through programs that have been recommended here) didnt work at all. I guess it helps being in an extremely dark sky area so doing 800 or 1600 looks awesome.

You bet, at 800 ISO and especially 1600 or higher you'll get "hot pixels." I don't think the noise reduction was designed to improve the 100 ISO shots, mainly the much higher ISO with longer exposures....the longer the exposure the worse it gets. Look at some of the Spaceweather shots of meteors or comets and you'll see many hot pixels. There are tricks to avoid this, but certainly noise reduction is a must either in or out of the camera for long duration images. I have a little program from http://www.mediachance.com called HotPixels (CCD noise eliminator). You might give it a shot.

Gene Moore

 

[Jayson Prentice]

I guess I'm wondering why you need to use such high ISO's in those cases? Just not as patient to wait for the shot if you were using ISO 100?

 

[Brian Emfinger]

I will definately give the program a try. Thanks and yeah I still get a few "hot pixels" in my meteor shots...take my best perseid this year for instance. There are several blue and red pixels in there that the camera didnt take out. BTW shot at ISO800, 25secs, F3.5, 18mm and cropped to the bottom 1/4 of image as meteor was at very bottom of shot.

And most of the stuff I am shooting a night is star trails/meteors/clouds (summer drought boredom!) and at ISO 800-1600 the exposures can be shorter while revealing much more detail and stars. ISO 100 just wouldnt work at all for 99% of the night stuff I do...you wouldnt see anything but a few bright stars probably.

 

[Jayson Prentice]

Alright, I see what shots you are talking about. Trying to get pictures to show the stars, etc. without getting the star trails which you will get when using exposures over 15 to 30 seconds. There is a program that I use for any type of 'noise' from pictures that might be a help if you want to skip out on the processing of the cameras noise reduction. NoiseNinja is a well regarded program and I've used it, even with an ISO 1600 night shot and it cleaned up exremely well.

 

[Dick McGowan]

Sorry I didn't clarify...I meant without the noise reduction filter my XT which I purchased back in 2005 (as Jayson stated), would not immediately buffer, unless it was 20 seconds or less. I thought this was normal until Darin shot longer exposures and would buffer immediately.

I've read over and over that the noise reduction filter isn't worth the extra time, it's better/shorter to just fix it in post-processing with a program like Noise Ninja or another plug in for photoshop.

For the meteors, I found that 400 ISO wasn't enough, and 1600 is too noisy for anything, so I used 800 (with f/2.8). Only time I use 1600 ISO is to test a shot out in complete darkness to see if it's in focus. Those hot pixels are easy to clone/stamp out, but I'm too lazy so most of the time I won't mess with it.

 

[Gene Moore]

As for high ISO shots... there is more than just sky/ astronomy stuff to use it on. If there was a night tornado generally I grabbed for my VX2000, then do frame captures to pull out singles. I've realized anyone can do that, so I'm trying to be a bit more classy about it and use the still camera. I managed to capture a laminar bulbus funnel almost overhead on the Dimmitt panhandle supercell in June. It was totally dark, but I had some ambient light from a gas well operation hitting the cloud base. The shot turned out silly pink (white balance went crazy on me....another topic for discussion), but that can be fixed in post processing. I tried it again Greensburg night on the Great Bend circulation/ tornado. I could see a nearby debris cloud, but that time I didn't get it. I'm still on a learning curve with night stuff that's not directly illuminated by a lightning bolt, it can be great fun.

Gene