Orion wide-field w/ Canon 28-300mm L

tkerr wrote in post #11462961
Sorry, but I am not a fan of those spikes that lens is creating. A bit too much distraction for my taste.

That's a matter of taste - I personally like star spikes, which is why I love my 6" RC.

Obviously smaller aperture = spikes (you can see it in regular photography as well). And using the largest aperture is not always the way to go. Larger aperture = softer image, especially in the corners (which would have been bad for this scene since the main objects are in the corners). Maybe I could have used f/6.3 or f/7.1, but I knew f/8 on this lens gave me good sharp images, so I went with that instead of experimenting. By testing, I knew that f/5.6 (max aperture at 300mm) gave me very soft images.

I really couldn't get much more out of the middle there. So intentionally darkened it. But I guess to make it "smoother", I should bring up the black point a bit. Here's a quick 5-minute re-edit:

FuzzSummit wrote in post #11464489
That's a matter of taste - I personally like star spikes, which is why I love my 6" RC.

I like 4 point natural star spikes in some images also, but IMHO, those shutter blade spikes are intrusive and distracting, and just don't look right to me.
My 100-400mm also reveals some spiking, but compared to this it is very subtle and looks more like natural star sparkle.

These two were shot with the EF 100-400 L
http://i68.photobucket​.com …im_Kerr/M31_wid​efield.jpg
http://i68.photobucket​.com …m_Kerr/M45-pleiades-1.jpg
At close look you can see the blade spikes.

Then there is something else having an effect on the image other than the aperture setting of the lens. At infinity focus a larger aperture should give you a greater resolution and detail in night sky DSO images.

What picture style and metering mode are you using?
I assume you're shooting and stacking RAW, correct?

tkerr wrote in post #11464808
What picture style and metering mode are you using?
I assume you're shooting and stacking RAW, correct?

Manual mode. Metering is spot (center), but since I manually set the shutter speed, aperture, and ISO, metering mode is irrelevant. Shot and stacked RAW.

FuzzSummit wrote in post #11464918
Manual mode. Metering is spot (center), but since I manually set the shutter speed, aperture, and ISO, metering mode is irrelevant. Shot and stacked RAW.

You're right it is irrelevant when adjusting shutter and aperture manually especially night sky long exposures.
But your comment that "you can see it in regular photography as well, and that larger aperture equals a softer image, especially in the corners" suggest that your getting softer images in regular photography as well. In that case then metering mode does matter.
Nevertheless, you answered my question anyways.

If you're getting a soft looking image of the night sky at larger apertures, are you sure it's not a focus issue rather than a aperture issue? The width of the star spikes is a good indicator of focus.

I understand and know what you mean about smaller apertures at the longer focal lengths. A disadvantage of a Zoom vs a prime.
When I shoot daytime pictures with the 100-400mm L, I have found the best f/stops are around f/7 and smaller to get the sharpest picture, especially at the longest focal length of the lens. I also use Spot Metering a lot, especially shooting birds in flight. Metering does have an effect on the exposure and sharpness throughout the entire image. That's when everything effecting the exposure and DOF are more noticeable. When I shoot pictures of the night sky however, the focus is at infinity on a subjects in very dim light at great distances using very long exposures, so DOF doesn't have the same effect on a DSO image like it would on a daylight terrestrial picture. I have to play with the focus to get the stars to look their sharpest all the way, or as close to the edge that I can. Sometimes it gets frustrating, especially when seeing is less than stable. I always count on cropping off some of the edges anyways, for reason other than just un-sharp focus.

tkerr wrote in post #11465326
But your comment that "you can see it in regular photography as well, and that larger aperture equals a softer image, especially in the corners" suggest that your getting softer images in regular photography as well. In that case then metering mode does matter.

I was referring to the spikes, not soft images. But regardless, most lenses are sharper stopped down than wide open.

No, because I did not change the focus between changing apertures (couple of minutes between test shots), and the f/8 images come out tack sharp throughout the frame; the f/5.6 images are sharp in the middle but "smeared" around the edges.

I honestly wasn't expecting wasn't expecting as good of a result from such a super zoom, but was pleasantly surprised.

Yes, focus is always the most troublesome thing to get right for me. I use a Bahtinov mask for my RC, but need to make one for my lens (once I settle on one for AP).

WOW! Amazing shot

Absolutely amazing! Great clarity in these photos.

that's a helluva lotta work for one shot, but, WOW, what a shot it is!!!

I'm trying to hone my PP skills, learn and grasp "overclipped" here.

When I look at both picts the RGB values in "black" are not zero, they are 8-13 over what appears just black space, meaning not true black (0,0,0) therefore some data still there, correct?

IMAGE IS A REDIRECT OR MISSING! HTTP response: 404 | MIME changed to 'image/png' | Byte size: ZERO

IMAGE IS A REDIRECT OR MISSING! HTTP response: 404 | MIME changed to 'image/png' | Byte size: ZERO

FuzzSummit wrote in post #11460066
Tried out the Canon 28-300mm L lens for astrophotography. Always wanted to get a wide-field shot of the Orion complex (including Horsehead and Flame), and it just fit in the FoV at 300mm.

Total exposure: 4hr 36min (80 x 15-sec + 80 x 30-sec + 76 x 1-min + 70 x 2-min)
Canon 40D + Canon 28-300mm L @ 300mm, f/8, ISO1600
Sirius EQ-G mount
Captured using ImagesPlus Camera Control, stacked in DSS, processed in Photoshop CS3

FuzzSummit;
I really like your hard work and result, and want to learn from you.
Since you are on a EQ mount the multiple "short" exposures is due to avoiding light pollution effects where taken? (No Astronomik CLS Light Pollution Filter use?)
You took 80 @ 15 sec, 80 @ 30 sec, 76 @ 1 min, 70 @ 2 min.
The EQ tracking keeps your shots crisp, the camera settings same, therefore longer gathers more data....so why the 4 time settings of 15 sec, 30 sec, 1 min, 2 min?

Why stop at 2 min, why not less exposures of longer duration? 4 min /shot or 6 min /shot?
Too much sensor noise then? or your polar alignment has to be spot on and shorter exposures won't be affected by not "perfect" polar alignment? Since no tracking/correction device used?

Are you also taking & stacking darks/bias/flat frames? (I assume so but not mentioned)

I've not stepped up to EQ mount just yet...but maybe soon.
Sorry for my many q's.
again, sweet picture.

Celestron wrote in post #11463008
Tim are you upset ? You sound kinda upset there .... , lighten up some it's Christmas .

Ron...you crack me up!

I think it's an great shot and would be very happy with the results as posted.
Sure it could be done different and we all have different likes and dislikes in the processing phase, but Fuzzsummit sharing his work with us is appreciated.

Greg

NovaTJ wrote in post #11468088
Ron...you crack me up!

I think it's an great shot and would be very happy with the results as posted.
Sure it could be done different and we all have different likes and dislikes in the processing phase, but Fuzzsummit sharing his work with us is appreciated.

Greg

I like both images the OP posted ! The second one is really good but the first one the detail is sharper and therefore makes easier for me to see . I envy the OP cause i've never been able to produce these type images but my excuse is i have older basic equip still and never been able to afford the higher $$ mounts . I've done good to just keep my camera updated . Been alot of health issues the last 7 years that keeps my pocket book empty but i still try !!

Thanks for all the continued comments.

mtbdudex wrote in post #11467509
Since you are on a EQ mount the multiple "short" exposures is due to avoiding light pollution effects where taken? (No Astronomik CLS Light Pollution Filter use?)
You took 80 @ 15 sec, 80 @ 30 sec, 76 @ 1 min, 70 @ 2 min.
The EQ tracking keeps your shots crisp, the camera settings same, therefore longer gathers more data....so why the 4 time settings of 15 sec, 30 sec, 1 min, 2 min?

Why stop at 2 min, why not less exposures of longer duration? 4 min /shot or 6 min /shot?
Too much sensor noise then? or your polar alignment has to be spot on and shorter exposures won't be affected by not "perfect" polar alignment? Since no tracking/correction device used?

The multiple exposures are for several reasons. The main reason is because Orion (mainly the core) is really bright and long exposures blow it out completely. Shorter exposures allow me to retain the brighter data and layer it into the final image. Since I'd never shot Orion with this lens before, I didn't know exactly how long of exposures I needed, so I went with a bunch of different lengths just to cover my bases.

The other reason is because this was my first try at 2-min unguided. I wasn't sure how accurate they would be, so also did the shorter ones just as backup in case the 2-min subs were not usable.

The reason I stopped at 2-min is because that's as long as I could get unguided without tracking errors becoming evident. Light pollution isn't a huge problem where I live - I can shoot 10- to 15-min guided subs without light pollution being a factor.

Yes, the subs were calibrated with darks (about 50 I think), 50 bias, and 50 flats.

The second edit I did very quickly just to lighten up the background and didn't do anything to the main objects themselves -- I'd probably be able to increase the contrast and "sharpness" if I spent a bit more time.

This mount (part of my RC imaging setup) was one of my splurges for sure - and it's not even the top of the line! I actually just started doing proper astrophotography this past fall (first light was Sep. 4). I've read and researched a lot, but am still learning a lot more.

Absolutely stunning!

Very nice work, loads of detail and very nice color

I agree completely on the points Tim made. f/8 is almost painfully slow and only forces more and longer exposures than necessary.

I'm not sure why but many or most of the images I see processed in DSS have a severe clip on the black point. I've never dabbled in DSS so I'm not sure if this is something not easily controlled in the stacking process or if the clip is occurring in PS in an attempt to hide background noise during final adjustments. I know I'm a pain about this but I hate to see someone work so hard to collect usable data and then toss a good percentage of it out in processing. I realize that processing is a challenging work in progress in this hobby (for myself included) so I try to suggest corrections that I've learned that are going to help improve results. Starlight makes pitch-black backgrounds in our astro images an impossibility, therefore doing so not only omits data but produces an artificial appearance. I look back at my early images and I'm 100% guilty of doing this myself, like I said it's a work in progress and I'm very grateful for the advice that was given to me along the way.

Keep up the great work FuzzSummit.