Posts Made By: Jeff Hapeman

Well, on a whim I decided to order a Canon 20Da. I have been doing a lot of wide-field astrophotography in the last few months with my 1Ds Mark II, and was really wondering if I could get better red response. I can make the 1Ds images look good, but it takes long exposures and lots of post-processing.

What kept me from the 20Da so far was that I wanted FF--believe me, once you go FF you never want to go back--and I didn't see a need for the specialty focus modes for the type of work I do. On top of that, I was concerned that daylight imaging would not be any good if they were letting IR leak in, and I still use my 20D for travel, when I don't want to lug the big gun around. Well, the recent S&T article convinced me that I had to give the 20Da a try. So I ordered one from Anacortes (gotta support Astromart, you know) and got in Thursday, just in time to take it with me to our lake house in northern WI, where the skies are dark. Well, except for the moon .

The attached image is a demonstration of just how good the 20Da is for astro-imaging. The details are in the shot, which is a side-by-side comparison with a 20D shot. I simply swapped the lens from camera to camera, and swapped cameras on the mount. The mount was a Takahashi Teegul Star Patrol II.

Post processing of both images was identical so as not to alter the results in any way. I simply pulled the RAW images into PS and used Russ Croman's Gradient Xterminator to kill the gradient from the moon, then tweaked the levels and curves identically on both images, and ran one shot of Noise Ninja. BTW, I turned on dark subtraction on both of these images.

A few things: The 20Da takes perfect images in daylight. I am not sure why Canon does not use the same filter on all of their cameras--I would love to be able to use my 5D or 1Ds Mark II for astrophotography with 20D red-response. The noise on the 20Da is about 1 stop better than the 20D. I measured this with a whole series of shots across all ISO settings, and it's nearly one whole stop better. The Canon 35mm f/1.4L lens is killer for this work but needs to be stopped down to about f/4 for maximum corner sharpness, minimum vignetting and CA reduction. CA is pretty bad wide open on long exposures. Unike the Hutech cameras, this camera is fine in the daytime and needs no special WB settings; the images of the night sky do not have an overwhelming red cast to them, either--the red nebulae are red, and that's it. Great job from Canon.

The 20D is going to go up for sale to some lucky photographer...it has less than 1500 shutter actuations on it. The 20Da can do everything it can do, and more.

Bottom line: Don't buy a 20D--get the 20Da. Since it includes the AC adapter, the price is actually very good, and the kit lens that comes with the regular 20D is trash, so the lack of a lens with the 20Da is no big deal.

I can't my image to load on my putzy dial-up connection up here, so here is just a link for now...



Jeff

OK, so there has been something done here to reduce the noise. The Sky & Telescope review mentioned the lower noise of the 20Da. I decided to check it myself, and like Alan Dyer, I used Noise Ninja to measure the noise. I fully sampled each image to get a good averaged noise measurement. I have also attached a photo that shows exposures from each camera. Please note that appearance alone is not enough to judge the noise; the images are reduced so much that you can't see the noise on the lower ISO images, but it was there.

Parameters: Both cameras set in the same dark room, no lens (just the body cap), 10-minute exposures. Images were shot in RAW, converted in Photoshop CS2 with the same settings--pushed 4 stops to exaggerate the noise--and then reduced and converted to jpegs. I turned off the Long Exposure Noise Reduction function on both cameras in order to measure the *native* noise of the camera.

Here is what we get for the 20Da:

ISO 3200, Noise 384, 161 Luminance, 223 Chroma
ISO 1600, Noise 287, 123 Luminance, 164 Chroma
ISO 800, Noise 71, 28 Luminance, 43 Chroma
ISO 400, Noise 13, 7 Luminance, 6 Chroma
ISO 200, Noise 3, 2 Luminance, 1 Chroma
ISO 100, Noise 1, 1 Luminance, 0 Chroma

And now the 20D "Classic":

ISO 3200, Noise 625, 285 Luminance, 340 Chroma
ISO 1600, Noise 310, 134 Luminance, 176 Chroma
ISO 800, Noise 151, 66 Luminance, 86 Chroma
ISO 400, Noise 99, 44 Luminance, 54 Chroma
ISO 200, Noise 33, 16 Luminance, 16 Chroma
ISO 100, Noise 20, 11 Luminance, 9 Chroma

Anyway you look at it, the 20Da has a lot less noise. The picture shows it nicely. The one confusing image is the ISO3200 image; here the 20Da looks brighter, but its not noise--at full size you can see it's very fine-grained. I suspect it is leaked IR that makes the image look bright. The Noise Ninja measurements show the real noise.

Anyway, to me the 20Da continues to be a champ: Lower noise, much-increased red sensitivity, yet still useful for regular day-to-day imaging. When you include the live focusing mode, included AC adapter, etc, the price seems much more reasonable. I can't wait for new moon at our house up north, with dark skies, so I can really give this thing a workout for some wide-field milky way imaging before the summer milky way is gone for the year.

Jeff

I picked up a Hutech-modified 20D from Klaus Priebe and took it out for a test Friday night--by luck I had a dark clear night the day I got some new gear! Overall, I like the improved red response but miss the focus feature on the 20Da. I will mess with both cameras for a while, but I think that I will end up either having my 20Da modified, or I will buy a modded 20Da. We shall see. Clearly, the modded 20D cannot be used very effectively for daylight photography, whereas the 20Da can be used for daylight photography--decisions, decisions.

This is a stack of 6 10-minute exposures at f/4 with a Canon 35mm f/1.4L lens--you need to stop it down to eliminate the CA around the stars--at ISO 800. No dark subtraction; at 32F it was not needed. Images were aligned and stacked in Registar and all post-processing was then completed in PS CS2.

Lots of cool stuff going on this image. You can even faintly see the Witchhead Nebula--appropriate for this time of year!

Jeff

Last night I waited (or should I say this morning 8O ) until the moon had set and then took this image of Orion's belt and sword region with a modified Canon 20D. I used the 135mm f/2L lens at f/5 to suppress CA, and shot for 10 minutes each subexposure at ISO 800. I meant to do a series of shorter exposures to layer in on the core of M42, so it wouldn't be so burned out, but I fell asleep :S . Either way, I like this, and with 50 minutes of total exposure, it got surprisingly deep. Dark skies are a wonder...and it's dark here in northern WI.

Jeff

Jim's post of his M31 made me realize I had a set of data from last full moon that I never processed--and it was a very clear night that night. I wanted to get 2+ hours of L and an hour of each color, but I fell asleep and decided to finish this later. Meanwhile, the data I got is pretty good, and shows the blusih star-forming regions rather well--which is gratifying--that has always been hard for me to capture. I suspect it was the excellent transparency. This is just 60m of L, and 20m of each color, 20m subs. This is a slightly cropped, reduced version. STL-11000XM and FSQ-106N.

Jeff

I am up north (far northern WI) for an extended holiday and have been cruising town each day looking at the berry trees and bushes for Bohemian Waxwings and Pine grosbeaks. So far I have been skunked on those two, but today I ran across a small flock of Cedar Waxwings at nearly eye height. The light was terrible, as it has been cloudy and dreary all week, but the flash did the job here. Finding a bird with a clean background and the righ pose was tough, and I only had about 10 minutes, as my wife was (im)patiently waiting in the car. This is a crop of about 95% of the original full frame; I took a tiny bit off the top to remove some dead space. No other adjustments except resize and very slight USM in PS.

Canon 20Da, 600mm f/4 IS, f/4, ISO 200, 1/400s, Better Beamer w/580EX @ -2/3EV fill.

Jeff

Anyone here do any imaging on their own at Mauna Kea? I know some Astromarters have...I am hoping someone on this forum has. I am going there for the second time in three weeks, and this time intend to take my Kenko SkyMemo, and two cameras and do some imaging from the Visitor's Center--which at almost 10,000 feet is not too shabby. I would like any tips anyone can provide who has been there, done that.

Thanks,

Jeff

This is an image I took back in Movember 2005 and just got around to processing. It is a stack of 5 10-minute exposures, aligned and combined in Registar using the Median-Mean combine function. All images were shot in RAW and then processed as 16-bit TIFF files until the final step. I wanted to get short exposure for the core of M42, but ran out of time. Note the large amounts of nebulosity throughout the whole image. If you know what to look for, you can see the Horsehead Nebula, M78, M42, and multiple NGC-catalogue nebulae. The camera was mounted on a Kenko SkyMemo mount for the exposures and the camera was a Hutech modified 20D, 135mm f/2L lens @ f/5.6 to reduce CA and ISO 800.

Jeff

I just realized I never posted the rest of my favorite Cedar Waxwing images from back around Christmas, so here are two more. Both were taken with the Canon 20Da and the Canon 600mm f/4 IS.

Jeff

This little chipmunk was doing its spring cleaning; there was huge pile of fresh dirt all around the entrance to its burrow. I got down very low to get a good angle on the chipmunk and braced myself with my knees to counter camera shake; that and the IS system let me shoot at 1/60s handheld at 560mm. This is a crop of about 85% of the original frame.

Canon 1D Mark II N, 400mm f/4L DO IS w/1.4x TCII, f/9, 1/60s, ISO 200.

Jeff