Eric Gage
sage
Reged: 12/13/05
Posts: 268
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I am getting a Canon T1-i. I want to use it for AP, but will most likely use it predominantly during the daytime. How well does white balancing compensate for the increased warmth of daytime photos with a UV/IR modified DSLR? Will I essentially be ruining the camera for daytime use?
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Eric
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WO 80mm 10th Anniversary
EZ Touch
PST
TV-85
Vixen Sphinx
Canon 500D (T1-i)
15" Obsession with ServoCat
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Jerry Lodriguss
Vendor
Reged: 07/19/08
Posts: 490
Loc: Voorhees, NJ
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If you get your camera modified, you certainly won't be ruining it for daytime use!
How accurately it will reproduce color will depend on how critical your needs are.
For snapshots, if you are not too picky, you can get by with just setting a custom white balance on a gray card for the illumination of the scene.
If you are more critical, in addition to the custom WB, you will want to also use a supplementary filter, either in front of the lens or in the camera body in front of the mirror, to take the place of the manufacturer's original filter.
Jerry
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A Beginner's Guide to DSLR Astrophotography
http://www.astropix.com
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Tonk
Post Laureate
Reged: 08/19/04
Posts: 4324
Loc: Leeds, UK, 54N
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The best solution is you use a X-Nite CC1 or CC2 colour correcting filter
http://www.maxmax.com/aXNiteFilters.htm
Scroll down to Colour Correcting Filters
Or alternatively Astronomics now do their own version, coded the OWB filter (Original White Balance)
http://www.astronomik.com/en/astronomik_owb-ccd_filter.html
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Tonk
Post Laureate
Reged: 08/19/04
Posts: 4324
Loc: Leeds, UK, 54N
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Actually - having just got a modded 450D last week and about to rush off to China for the eclipse, it occured to me that having one of these filters would allow me to not worry about WB correction while clicking off exposures - plus I can photo my travels without pansying around with a grey card. So I've just ordered the Astronomics EOS clip-in version of the OWB filter.
This post just cost me!!!! 
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Televue 85, GM-8/Gemini, Canon 40D (unmodded), Canon 450D (modded w/Astronomiks clip-ins - UV/IR, OWB)
Coronado SM60/BF10, Baader Herschel Wedge
Leeds Sky Clock Ripon Sky Clock
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WarrenS
scholastic sledgehammer
Reged: 03/04/08
Posts: 841
Loc: Orange County New York
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Just remember you can't use clip ins with Canon EF-S lenses as they protrude too deeply into the camera body. My Astronomik clip-in already has circular marks from non EF-S lenses faintly etched onto the metal frame of the filter.
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Warren
Astro-Tech 127EDT
Celestron Onyx 80ED
Astro-Tech Field Flattener
C8 (circa 1983 Orange Tube)
Atlas EQ-G, Orion SSAG
Canon 135mm F2.8
Canon 40D, Astronomik CLS clip filter
Leica, Minolta binos
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Tonk
Post Laureate
Reged: 08/19/04
Posts: 4324
Loc: Leeds, UK, 54N
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Quote:
Canon EF-S lenses as they protrude too deeply into the camera body
Check - already have that figured. Don't have any and so far after 1 week no marks on my UV/IR block filter
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Televue 85, GM-8/Gemini, Canon 40D (unmodded), Canon 450D (modded w/Astronomiks clip-ins - UV/IR, OWB)
Coronado SM60/BF10, Baader Herschel Wedge
Leeds Sky Clock Ripon Sky Clock
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WarrenS
scholastic sledgehammer
Reged: 03/04/08
Posts: 841
Loc: Orange County New York
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I was sure you knew Tonk, my too brief post was actually directed at anyone who may have purchased a Canon camera with a kit EF-S lens and may not have been aware. 
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Warren
Astro-Tech 127EDT
Celestron Onyx 80ED
Astro-Tech Field Flattener
C8 (circa 1983 Orange Tube)
Atlas EQ-G, Orion SSAG
Canon 135mm F2.8
Canon 40D, Astronomik CLS clip filter
Leica, Minolta binos
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Eric Gage
sage
Reged: 12/13/05
Posts: 268
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Thanks for the feedback. I have been reading Covington's book and although the performance differences between unmodified and modified DSLR's are apparent, they aren't as severe as I had thought. I've come to the conclusion that I'd rather have optimal daylight performance and good astrophotography sensitivity than to have good daylight performance and optimal AP response.
I'm going to cancel my modified 500D order and replace with a stock 500D (t1-i) instead. I'll still try to post once I get the hang of it on the deep sky.
Thanks again.
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Eric
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WO 80mm 10th Anniversary
EZ Touch
PST
TV-85
Vixen Sphinx
Canon 500D (T1-i)
15" Obsession with ServoCat
Edited by Eric Gage (07/04/09 07:54 PM)
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Nils_Lars
Post Laureate
Reged: 01/04/08
Posts: 3260
Loc: Santa Cruz Mountains , CA
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I have a X-nite filter and it works well for my 400D for happy snaps of the family and such.
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Erik
Orion Atlas Self Hypertuned (EQMOD)
Orion ED 80
Williams Optics VII reducer
Celestron 8" SCT
Orion Starshoot Autoguider
PHD guide
Canon 400D Hap Griffin Mod w/Baader filter
Astronomik clip-in LP filter and 12nm Ha
Stilleto CVF and Bahtinov mask
Tamron 75-300mm&28-80mm lenses
NexImage webcam
http://www.flickr.com/photos/31986095@N05/
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zAmbonii
scholastic sledgehammer
Reged: 01/19/08
Posts: 803
Loc: Ypsilanti, MI
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I've never done a direct comparison between my modded 300D and my unmodded 300D (same exposure length). I never tried shots longer then 2 minutes with my unmodded camera because, at the time, I didnt have a light pollution filter that prevented saturation at 2 minutes, nor a mount that allowed me to take longer exposures without star trailing. I have both now and I have pushed it to 6 minutes with my modded camera)
From comparison shots there seems to be quite a bit of difference.
W. Veil unmodded
W. Veil modded
Crescent nebula unmodded
Crescent modded
m16 unmodded
m16 modded
m20 unmodded
m20 modded
There is definitely a difference, but the decision is up to you. The modded cam will give up up to around 9x more response in the H-alpha regions.
If you arent satisfied with the umodded, you can always send your camera to get modded....and there is always a good second option---buy a cheap older model like I did with my 300D (you can get a body only for around $200) and do the mod yourself. Prices are always coming down for the older models and is always an option for the future.
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Check out my Astrophotos on Flickr
C6-N 150mm f/5 Newtonian
CG-5 ASGT mount
Canon 300D self modded + IDAS LPS-P2 FF
Meade 70AZ + Meade DSI for autoguiding
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justabob
Carpal Tunnel
Reged: 05/05/07
Posts: 1636
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Quote:
So I've just ordered the Astronomics EOS clip-in version of the OWB filter.
This post just cost me!!!!
Hey Tony I just ordered one as well. My thought is I will be more apt to use one of my modded cameras instead of the nikon cool pix.
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http://www.pbase.com/rkn/astro&page=all
Vixen Sphinx SXW
Meade sn6
Canon EF 200mm f/2.8L II USM Lens
Hutech 1000d
Self modded 350d
DSI PRO II
Bob
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Tonk
Post Laureate
Reged: 08/19/04
Posts: 4324
Loc: Leeds, UK, 54N
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Quote:
differences between unmodified and modified DSLR's are apparent, they aren't as severe as I had thought
Well it was severe enough that I totally gave up on my unmodded 10D and got a modded 450D to handle H alpha. The difference for the 10D is with its original (bonded in) filter the transmission of H alpha is ~15%. The modded 450D has H alpha transmission >90%. Thats exposures at least 6x shorter to grab the same amount of H alpha
Zambonni's comparative images are a very good gauge. The Veil Neb is pretty well instructive. Without the mod you certainly get the OIII green light, but in comparison the H alpha light is pretty well non existant. With the mod in place the levels of green and red light are much of equal strength.
Then again I've been imaging for 5 years and avoided red stuff. There is plenty of other satisfying subjects (and they are usually things that others pass over in the quest for glowing red gas)
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Televue 85, GM-8/Gemini, Canon 40D (unmodded), Canon 450D (modded w/Astronomiks clip-ins - UV/IR, OWB)
Coronado SM60/BF10, Baader Herschel Wedge
Leeds Sky Clock Ripon Sky Clock
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Tonk
Post Laureate
Reged: 08/19/04
Posts: 4324
Loc: Leeds, UK, 54N
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Humm - I just looked at Covingtons comments and note that he's comparing stuff to the Canon 20Da. This was the "astronomers" edition of the 20D. This camera had a different filter that extended further into the red end of the spectrum but didn't give you the 90%+ transmission that a full filter removal gives you. It was a compromise that still allowed daytime photography but gave you a fighting chance at nebula photography. The actual H alpha transmission was somewhere between 30% - 50% (I'll see if I can locate the wavelength transmission chart). So in reality Covington is not comparing the same things - he certainly not comparing to a "modded" camera. Yes at 30% transmission you can get reasonable H alpha recorded - but you will have to expose 3 - 4 times longer to match the signal from a modded camera.
So be aware many unmodded Canon cameras have worse H alpha transmission compared to the compromised 20Da and all will be far worse than a true modded camera. You will need to check what it really is for the model that you are choosing
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Televue 85, GM-8/Gemini, Canon 40D (unmodded), Canon 450D (modded w/Astronomiks clip-ins - UV/IR, OWB)
Coronado SM60/BF10, Baader Herschel Wedge
Leeds Sky Clock Ripon Sky Clock
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Tonk
Post Laureate
Reged: 08/19/04
Posts: 4324
Loc: Leeds, UK, 54N
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Here you go. Christain Buil has measured the Canon 350D built in IR/UV block filter and this gives 19.5% transmission at H-alpha
http://www.astrosurf.org/buil/350d/350d.htm
Meanwhile I've looked up Astronomiks transmission graphs for their filters and a replacement astronomical UV/IR filter gives 95% transmission, while the restorative filter (OWB) takes this back to 30% for H-alpha. I've superimosed the charts to allow you to see this
The H-alpha line is the second from right green spike. The grey area is human eye sensitivity by wavelength (human eyes don't see H alpha well - unless its very bright e.g. observing the sun via solar H-alpha filters). The strong red curve is the astronomical UV/IR cut filter, the paler one is the OWB restorative WB filter
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Eric Gage
sage
Reged: 12/13/05
Posts: 268
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Thanks for that great information. In referring to Covington's book, my point was not that the mod isn't better--it's that, for me, the stock camera is adequate.
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Eric
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WO 80mm 10th Anniversary
EZ Touch
PST
TV-85
Vixen Sphinx
Canon 500D (T1-i)
15" Obsession with ServoCat
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Samir Kharusi
scholastic sledgehammer
Reged: 06/14/05
Posts: 969
Loc: Oman
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I am becoming rather cynical as regards all these discussions on WB for modded cameras. The reality is that 90+% of daytime shooters do NOT use Custom WB for their photography, the ONLY accurate method for all shooting. They depend on AutoWB, so at best one could say that either they do not care all that much for accurate WB, or at worst that they have no clue as to what they are talking about. Most of us are simply looking for comfort, rather than use our own critical eye. We were all very contented to use Daylight color film for all our shooting... Color balance also varies between camera makes. Anyone using camcorders can easily see the difference between a Sony video and a Canon video. The differences in color rendition between the latest LCD HD TVs are huge (check the reds) yet we simply accept the renditions with only a very few die hards actually color balancing their home theatres. This is the actual amount of differences between modded cameras and unmodded (both using Custom White Balance). It's really up to the fastidious user to decide whether he needs a supplementary color correction filter or not, but at least the samples are there for your own judgement. Considering the effort we put into a single astro image (hours and hours), compared to a zillion daytime pics, I really am way in favor of modding to optimise where the hours are spent. Custom White Balance does an excellent fix for daytime pics using modded cameras. And who actually gives a toss for "accurate" color balance anyway? Most consumer cameras are designed deliberately to yield a "healthy" complexion to sun-starved Caucasians rather than accuracy with color charts 
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Bored? Peruse my website:
http://www.samirkharusi.net/
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justabob
Carpal Tunnel
Reged: 05/05/07
Posts: 1636
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Quote:
for me, the stock camera is adequate.
It was for me as well. Until I attached it to a quality gem mount that was capable of 5 to ten min exposures. I then sold my Obsession and two other dobs and modded my cameras.
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http://www.pbase.com/rkn/astro&page=all
Vixen Sphinx SXW
Meade sn6
Canon EF 200mm f/2.8L II USM Lens
Hutech 1000d
Self modded 350d
DSI PRO II
Bob
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