Another first moon shot. (Tamron 180mm+2X TC)

Taken last night with a Tamron 180mm macro lens with 2X Teleconverter. It is a stack of 6 images, bit of PP in PS.

Nice exposure, George, but severely over-processed. Easy does it on the sharpening.

Don

My eyes went right the the limb. Very distracting from the rest of it.
What post processing did you do with Photoshop?
I agree with Don that it looks over-processed. But don't feel lonely, that's something many of us have had to struggle with from time to time. It seems as though it doesn't take much to go from not quite enough to too much.

Thanks, for the comments! Brightness, contrast, sharpness was adjusted in PS.
Unfortunately it wasn't spectacular enough from me straight out of the camera..
I'll keep shooting and hope for the best. Any tips you guys have when shooting with
a telephoto lens instead of shooting through a telescope?

Hi George,

360mm is enough to get a pretty detailed image. Stability of the platform (hopefully a decent tripod) is critical.

Use high enough ISO to get a shutter speed no slower than about 1/(focal length x 2), or 1/720 in this case, while stopping down the lens at least 2 full stops from wide open. Use a remote shutter release cable if you have one, otherwise use the camera's self timer so you won't be touching the camera when the exposure is made. Enable mirror lockup.

Don't rely on auto focus - manually focus and review the results, or use LiveView while zooming in to manually focus. Don't depend on LiveView either, though, until you have verified its accuracy for focusing. It's best to visually evaluate the results of test exposures by downloading the full images to a PC if possible. If not, review the images after capture on the camera's LCD and zoom in to evaluate focus.

Shoot in RAW mode always for astrophotography.

Stacking is of limited value for the moon - I won't say don't do it, but usually if there's any benefit achieved by stacking lunar shots over any single frame, there's at least one single frame that is as good as or better than the stack. Unless atmospheric conditions are truly horrible, they don't affect lunar shots much because of the scale. And because of the very high brightness, shot noise, which affects long exposures of faint objects, isn't a significant issue, so you're probably better off not stacking.

Another issue with stacking lunar images when the camera is mounted on a conventional tripod is field rotation, which means that the frames need to be rotated as well as translated in order to get a good alignment. The degree of field rotation depends on the elapsed time between the first and last image in the stack. Properly stacking lunar images requires specialized software like Registax. Software designed for processing deep space images, like DeepSkyStacker, can't do it, and doing it manually in Photoshop would be problematic if significant field rotation is present.

Don

Quick question. Would the 55-250 IS lens be good enough for a moon shot?

Hopefully you shoot and save your images in RAW format so you can actually work with them in PS.

Ditto what Don said about stacking images of the Moon. With the exception however, if you are using Video such as when using a Web-Cam, Then you would want to sort through and stack your best frames, and, even then you're still time limited.
Shooting from a DSLR, with camera lens, or even using a telescope, stacking isn't necessary. One stable shot with the right settings and good exposure is all you need.

Brain Mechanic wrote in post #10257079
Quick question. Would the 55-250 IS lens be good enough for a moon shot?

Yes, at 250mm the full moon's image will fill about 10% of the width of a Canon APS-C sensor, so you will have enough pixels to work with.

I don't use IS, but from what I have heard it may be better to turn it off for shooting the moon, at least if you have the ability to stabilize the camera on a tripod.

Don

DonR wrote in post #10257067
Hi George,

360mm is enough to get a pretty detailed image. Stability of the platform (hopefully a decent tripod) is critical.

Use high enough ISO to get a shutter speed no slower than about 1/(focal length x 2), or 1/720 in this case, while stopping down the lens at least 2 full stops from wide open. Use a remote shutter release cable if you have one, otherwise use the camera's self timer so you won't be touching the camera when the exposure is made. Enable mirror lockup.

Don't rely on auto focus - manually focus and review the results, or use LiveView while zooming in to manually focus. Don't depend on LiveView either, though, until you have verified its accuracy for focusing. It's best to visually evaluate the results of test exposures by downloading the full images to a PC if possible. If not, review the images after capture on the camera's LCD and zoom in to evaluate focus.

Shoot in RAW mode always for astrophotography.

Stacking is of limited value for the moon - I won't say don't do it, but usually if there's any benefit achieved by stacking lunar shots over any single frame, there's at least one single frame that is as good as or better than the stack. Unless atmospheric conditions are truly horrible, they don't affect lunar shots much because of the scale. And because of the very high brightness, shot noise, which affects long exposures of faint objects, isn't a significant issue, so you're probably better off not stacking.

Another issue with stacking lunar images when the camera is mounted on a conventional tripod is field rotation, which means that the frames need to be rotated as well as translated in order to get a good alignment. The degree of field rotation depends on the elapsed time between the first and last image in the stack. Properly stacking lunar images requires specialized software like Registax. Software designed for processing deep space images, like DeepSkyStacker, can't do it, and doing it manually in Photoshop would be problematic if significant field rotation is present.

Don

Thank you Don, for your detailed advice.To describe the process, I had done most of your suggestions, Live view 10x for finding focus, manual focus, remote shutter. I used low iso, because I was worried about the noise, so my shutter speed was relatively slow.
Also my tripod isn't a decent one, it's on my list to get. I did use Registax, but took a while to figure out how it works, manually aligning all the shots. It was shot in Raw+jpeg and I've used the Jpeg for stacking. I'll look at my single raw shots, see if I have a good single frame I can use. Also I have a Canon 24-70L that is a 2.8 and works well with the Tamron 2X, but is it worth using it for it's better image quality? Also I haven't use mirror lock up, but I'll try to do all these tonight, see, how they come out. Thanks again! Also, what's the advantage of using a webcam, instead of using the HD video function on the camera?

I haven't used a webcam to do astronomy yet, but I've seen amazing results. I guess I have lots of reading to do on this subject, to learn all the tricks.

Brain Mechanic wrote in post #10257079
Quick question. Would the 55-250 IS lens be good enough for a moon shot?

Hey Brain Mechanic, firstly - great profile pic!!!

Secondly, I concur with DonR ... mainly to sound like I know what I'm doing by backing someone who really knows their stuff and has the pictures and posts to prove it.

I'm still only new to shooting with a DLSR (the moon is about as far I've gone in Astrophotography at the moment until I get to darker skies/an actual mounted telescope or warmer weather). Good tripod, cable release in burst mode (I set 5 photos with a 5 second delay in between to avoid any shake that's going on), comfortable chair, constantly check focus before and after by reviewing the images.

I've seen people say f/8 is the sweet spot for most lenses but f/11 is what you want for moon pics. Haven't tested different apertures too much as I'm still playing with lenses ... I have been trying to work out how focal lengths work in relation to the olde 12x Optical system that my point-n-shoot used ... the rough formula of focal length/50 kind of works but comparing a 15MP to 5MP camera confuses my math, so I've just gone for the longest thing I can get my hands on.

So below (and linked to a 100% version) is my own rough case study of different focal lengths. I soon learnt early on my 17-85mm lens was not long enough for the moon ... I then borrowed a 90-300mm which reached further but still not long enough ... then bought the 55-250mm IS (slightly shorter but with IS!!!) cos I needed something and it gets rave reviews and apprently best bargain in it's class, I concur - it's great but still not long enough ... so I recently grabbed a 2nd hand Tamron 200-400mm and a Sigma 2x TC and this is my moon study at different focal lengths:

Shrunkened version (reduced to 800pixels wide):

HTTP response: 404 | MIME changed to 'text/html' | Byte size: ZERO

Great comparison!!

It seems that in terms of sharpness the 250mm was better?

George7806 wrote in post #10257429
I did use Registax, but took a while to figure out how it works, manually aligning all the shots. It was shot in Raw+jpeg and I've used the Jpeg for stacking. I'll look at my single raw shots, see if I have a good single frame I can use.

Registax will also handle the RAW files from the T2i if you want to stack them and compare the results. You will always be better off starting with RAW files rather than JPEG, or convert RAW to TIFF if you're using software that won't handle RAW.

George7806 wrote in post #10257429
Also, what's the advantage of using a webcam, instead of using the HD video function on the camera?

Good question! I guess the answer depends on what kind of internal processing the camera does to convert the images to video, and whether you have any control of that process. Ideally, the images would be streamed to a video file without any manipulation other than what's needed to encode them in the output format. We know the T2i doesn't do that, because there are more pixels in the sensor than in the HD output format. I'm assuming the T2i uses the entire sensor and resamples the images to reduce the resolution when outputting video. It may also do some smoothing, etc. So, the question is what exactly happens inside the camera? And then, what is needed to get the MOV format output by the T2i into Registax or another appropriate application? I don't know the answers to these questions.

I have a Philips SPC-900NC webcam that I use for astrophotography sometimes, and it has higher resolution (pixel density) than my Digital Rebel XT, but the T2i beats any webcam I know of as far as raw pixel density. Why don't you try it and let us know how it comes out?

Generally, though, the webcam excels at very long focal lengths and imaging very small objects, like Jupiter, Saturn and Mars, where the Earth's atmosphere blurs a large percentage of the images. The webcam allows you to capture many images in a short period of time so that you can pick the best and stack them. If you were shooting extreme close-ups of the moon the same would apply, but at more normal focal lengths you're probably better off aiming for a few good shots.

Don

Brain Mechanic wrote in post #10257754
Great comparison!!

It seems that in terms of sharpness the 250mm was better?

Like I said ... I'm still fairly new with DSLR'ing so this is not a scientific 100% apples for apples comparison ... more for working out what length gives you what sort of magnification, not a fair comparison of which lens is "better". Overall though I am very happy with the 55-250mm ... price is definitely right for my level (IQ-wise), light weight and IS means I don't need to lug around my tripod ... would be awesome if there was a 2.8 version but then why not go 70-200mm I guess.

The 250mm shot was shot end of March, about 3 months after the 300mm shot (January sometime - two full moons can't remember which one this was), so I'm probably slowly getting better at shooting the moon, PLUS I believe atmospheric conditions make a huge impact?! I could see a mirage effect the nights I've been shooting at the 800mm end.

I'm now trying to master the "800mm" (200-400mm with 2x TC) ... which has a bunch of new challenges ... in general TC seems to make everything twice as soft, light is harder to metre and focusing is three times trickier ... PLUS the lens is heavier and everytime I breath on the focusing ring at the front to adjust it the whole thing shakes and takes about 3-4 seconds to calm down on my Manfrotto ... hence my 5 sec delay between bursts.

Still, I'm loving the Tamron and hear that big lenses require more of a learning curve ... if there's any other tips and tricks more than happy to try them, anyone?

George7806 wrote in post #10254226
Taken last night with a Tamron 180mm macro lens with 2X Teleconverter. It is a stack of 6 images, bit of PP in PS.

Very nice for your first go at it. It is much better than many of my early attempts. In the beginning, I figured that if a little sharpening was good then surely more must be better ... right? Anyway, image sharpening is a tough subject to master and it probably helps to be a bit OCD about such things if you want to reach Nirvana in astrophotography.

Most sharpening is based on using unsharp mask which produces halos around high contrast edges. An effective way to deal with this is by creating edge masks that only sharpen along mid-tone edges while ignoring the dark and light high contrast edges. I would highly recommend the book "Real World Image Sharpening" by the late Bruce Fraser (later revision by Jeff Schewe) as a great text if you plan to do much image editing, especially printing. Also, a little known fact is that even reducing the size of an image uses built-in unsharp mask to restore crispness to edges. Unfortunately, the effect is normally too strong for certain subjects like astro, macro, and bird photography. Most software has no option for turning off the USM part of rsizing. However, by using the bicubic algorithm rather than the bicubic sharper in Photoshop, halos can be held to a minimum.

DonR wrote in post #10257067
...Stability of the platform (hopefully a decent tripod) is critical.

Use high enough ISO to get a shutter speed no slower than about 1/(focal length x 2).

Don't rely on auto focus - manually focus and review the results, or use LiveView while zooming in to manually focus.

I strongly agree with the above statements except for the shutter speed. That rule certainly applies to hand held shooting conditions, but for a heavy duty rock solid tripod, there is not much reason that one could not go to a much slower shutter speed except that many tripods are not all that stable.

DonR wrote in post #10257067
... Stacking is of limited value for the moon - I won't say don't do it, but usually if there's any benefit achieved by stacking lunar shots over any single frame, there's at least one single frame that is as good as or better than the stack. Unless atmospheric conditions are truly horrible, they don't affect lunar shots much because of the scale. And because of the very high brightness, shot noise, which affects long exposures of faint objects, isn't a significant issue, so you're probably better off not stacking.

There are times when stacking moon images is useful, as you said. Rather than looking at stacking lunar images as a technique for noise reduction, view it instead as a tool for refining edge details. Most of the time, people only consider mean value stacking, but that will tend to soften edges at the expense of reducing noise. I use median value stacking on moon images. It is not very effective at noise reduction, but its main value lies in enhancing edges. The median filtering can result in some image distortion if the quality of the images being used are not especially good. A valid point that Don makes is that there is often a very sharp image and then some so-so images. Using the so-so images will ruin the results regardless of processing is done. Make certain that all of the images that are used in a stack are the best quality that you can possibly get or else do not even consider using them. Even one bad image will stink up a stack.

DonR wrote in post #10257067
... Another issue with stacking lunar images when the camera is mounted on a conventional tripod is field rotation.

That definitely can be an issue if one wastes too much time capturing the images and does not do some planning ahead. However, by planning the time frame when the moon is near its highest elevation (essentially due south if you are in the northern hemisphere) and setting up the tripod mount so that most of the rotation will be in azimuth, a conventional tripod mount can be used with very little field rotation if all of the images are captured in just a few minutes. Obviously, actually doing this becomes problematic as the moon is closer to the zenith at your location. But, then most camera tripod mounts will not accommodate pointing the camera straight up. In this situation, shoot when the moon is lower in the sky and track in elevation.

Sometimes field rotation is a non-issue such as last night, May 26, at about 10 PM CST. It took me less than a minute to shoot my images and essentially all of the motion was in azimuth. Field rotation was down in the noise during that time frame.

legoman_iac wrote in post #10257732
I've seen people say f/8 is the sweet spot for most lenses but f/11 is what you want for moon pics. Haven't tested different apertures too much as I'm still playing with lenses ...

That is true for a lot of lenses, especially if they are zoom lenses. However, the high quality prime lenses are typically tack sharp even at their greatest aperture. Just do not go too small in aperture or the diffraction pattern will start to become evident.

One other point when using a good solid tripod is that I would recommend keeping ISO as low as possible and let the shutter speed get as low as 1/50 second before increasing the ISO to a higher value. With my camera and lens (Canon 7D and 400/5.6 lens plus 2X and 1.4X TC for a FL of 1120 mm), the moon which has an angular diameter of 0.5 degrees represents a 2300 pixel width and height on the camera's sensor. With an approximate lunar rate of 0.0042 degrees/second, it would require a shutter speed slower than 1/20 second for motion blur to equal one pixel. (The angular resolution of the sensor with a 1120 mm FL lens is approximately 0.0002 degrees/pixel. At 1/80 second shutter speed which i used for my images yesterday, the moon traverses 0.0000525 degrees -- much less than the resolution of the sensor and probably somewhat less than the resolution of the lens/TC combination used.

Thanks, for all the comments, I've got lots of new info, how to make my shots better, I will try and compare. Also since I took a short HD video the same night at full HD with 60 fps, I will convert it into mov, and see if I can stack some of those frames. Let's just hope that focus was tack sharp