« on: January 08, 2014, 11:51:36 PM »
These are my supertelephoto lens caps. http://amzn.to/1aIVngL
That is freaking awesome! I'll have to try that for my 600/4 L II. I assume that is either a 500 or 600 in your Bataflae?
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These are my supertelephoto lens caps. http://amzn.to/1aIVngL
From the CNET article:QuoteLarger TVs or closer seating distances make that difference more visible, as do computer graphics, animation, and games...
Like I was saying, if someone is looking at something inherently blurry the resolution of it isn't going to matter.
I recently read that in the EU they're looking at including 100hz (double the standard 50hz PAL frequency) in with the 4K broadcasting spec. The original NHK UHD spec also included a 120hz refresh rate to help improve the image. I have to wonder if the archaic 24hz Hollywood standard frame rate isn't partly responsible for much of the negativity surrounding 4K?
It's good to see that you're aware of the difference, a significant majority of the people I talk to are completely unaware. In my opinion it basically amounts to false advertising.Bravo I'm informed of the lies of the industry. Dude, get over it! It's just a marketing term to highlight a new feature that I am particularly thankful for.
Lower power consumption is _always_ welcome.
I'm just as happy as you are that the industry has switched to LED backlighting, it just should have been named differently.
60D shooting video through an 8 inch telescope.... 1900 frames extracted from the video and run through registax. The atmospheric distortion was really bad that night and all the frames are poor, but the result was much better than any individual frame.Still playing and learning......
Single frame, or stack from a web cam? If you have a web cam, you might try setting up some kind of contraption to attach it to your lens, and let it rip for about a minute. Then, you can use the tool Registax to identify the best frames, stack em, and you can get some really AMAZING planetary results. Each individual frame looks super crappy, but people have been creating some truly awesome, and often highly detailed, results with Registax and around 1000-1500 frames from basic web cams. Even some RGB astrocams like Celestron's Skyris is just a webcam in a more advanced enclosure with astro-specific features.
I want to try digiscoping through the telescope, but for the last two months the only times it has been clear at night the temperature has been -25C or colder.... Right now it is freezing rain, tomorrow night is supposed to be minus 29.... A wild winter!
I played with DSS early on, but never really got on with it. I've gone to PixInsight but it isn't cheap and has more of a learning curve to it.
Here's a more recent attack on it. 450D with all filters removed. Astronomik CLS-CCD. Sigma 120-300 f/2.8 OS EX at 300mm f/2.8. 2 minute exposures. Note the stars don't suffer the red glow the 1235L does.
Due to the light pollution where I live, I can't do really long exposures even with filters. I can perhaps get 4 minutes usefully with a narrowband filter at f/2.8, after which I'm just picking up the noise floor.
Still playing and learning......
This is imho the most inspirational thread I have read in this forum for quite a while!
I have never tried astrophoto myself (except when I was lucky to borrow the 800/5.6 with a 2xIII TC to take picture of the moon, but that would hardly count as the moon is very bright so the exposure time is very short).
I have been reading this whole thread on my ipad retina, and it has quite good resolution. However, due to the restrictions on image size here in CR, I would have loved to see full resolution images of your beautiful pictures if you guys have posted them somewhere else?
Any problem when you use those fast lens with the Astronomik filters?? I thought they are design for f3.8 to f15...
By the way, now they have clip on filters for Canon 5D and 6D full frame camera, but I think you had to lock the mirror in up position to install the filters, so might not be that useful if you need the viewfinder to aim.
Is that right? I'll have to see - using the 5DIII would improve things a lot. One thing that's relevant in any case is the Astronomik EOS clip filters (for 1.6 crop bodies) actually fit into the super telephoto lens rear filter holder (on my 500 II at least). Sadly my tracking mount can't handle the weight of that lens and body combination, so I've never made much use of it - but it's worth knowing.
As for aperture, I suspect it's the reason I get a lot of halos around stars. They are, as you say, rated for medium to narrow apertures (by lens standards). With the UHC filter, many stars get bright magenta halos, which can be a pain to remove if your main subject is a red/pink nebula. Nonetheless, other than that, I've found no problems, and a tradeoff worth making in my experience.
Edit: here's one of my early attempts at Andromeda galaxy with the 135L at f/2, CLS filter on 600D (unmodified). 100% crop, processed. I have got a bit better since then...
I'd have been very happy with that! Andromeda is a target I've struggled with. Partly because it's hard to locate (no very bright nearby stars) and partly my filter seems to bring out hydrogen emission nebulae much better than galaxies or reflection nebulae (e.g. the Pleiades).
Incidentally, the 135L is a lens I've considered as my next step for this work. Would you recommend it? The 100L macro has done pretty good service so far, but I'd love more reach (and as I say, the 500L II is too heavy for my tracking mount).
Reprocessed a few times with DeepSkyStacker. Tweaking the final result is a real PITA, but when you figure out how to do it right, the results are much better:It's -33C here tonight.... I'm not terribly worried about peltier coolingI dunno if my experience is relevant, but I held out for as long as I could before I got a tracking mount. You can do good stuff with short exposures if you go through the proper motions of dark and flat frames, and stacking a lot. Dark skies/astro filters probably make the most difference beyond that. I do all my aligning and stacking by hand in Gimp (I'm not sure any of the good free astro stack/align software is available for Macs, but anyhow that's what I'm used to now). Having said that, a tracking mount can push things further than anything.
You can extract a certain degree of quality from non-tracked stacking, but there is a limit. With short exposures, you have a very low signal strength. While you can improve SNR with stacking, you can't improve the actual image signal strength beyond a certain point, so you can never get the nice fine detail that a long exposure gets you. I've spent about two months now trying...and the shot above is about as good as I think I'll be able to do without tracking (or exceptionally dark skies, which are really rare and hard to find.)
I have done a fair amount of manual stacking in Photoshop, and the results can be quite good. Stacking software, especially the more complicated versions like DSS, Nebulosity, etc. are much more capable, but they have a high learning curve, and often their toolsets are difficult to use. I have avoided DSS up till now, but I just spent the bulk of the day working on the shot above, and I think I finally have it figured out. It's a bit noisy (it got much too cold last night, and I packed it in before I took dark frames and bias frames), but that can easily be delt with.Exposure times of tens of seconds up to minutes can be transformative.
Indeed! I can't wait to get my hands on the Celestron EdgeHD 11" CGEM DX. I had my eyes on a 5D III for my next photography, but I think I'm going to move the telescope to the top of my list. I am curious to see how the 7D II turns out, and for astrophotography, no DSLR will really do what I want, so I'm planning on getting a monochrome CCD with the biggest pixels I can find (probably around 9µm to 9.5µm, or perhaps 5µm with the option to 2x2 bin) an dual-stage peltier cooling (which gets you up to around 77% Q.E.) I'll then be able to filter Ha, Hb, Luma, R, G, B, and any other bands independently, and blend them in post for very high detailed, full-color wide band images.
I have an 8" Celestron with a tracking mount.... I have tried the 60D on it, but there is WAY to much noise... My friend's 5D2 work's much better, but it is an hour's drive away and that rules it out most of the time...
I have been thinking of getting one of these.... http://focusscientific.com/osCommerce/catalog/product_info.php/cPath/94_47/products_id/649
I dunno if my experience is relevant, but I held out for as long as I could before I got a tracking mount. You can do good stuff with short exposures if you go through the proper motions of dark and flat frames, and stacking a lot. Dark skies/astro filters probably make the most difference beyond that. I do all my aligning and stacking by hand in Gimp (I'm not sure any of the good free astro stack/align software is available for Macs, but anyhow that's what I'm used to now). Having said that, a tracking mount can push things further than anything.
Exposure times of tens of seconds up to minutes can be transformative.
what about following (naive fallacy):
EOS 5D Mark II
Introduced November 2008
EOS 5D Mark III
Introduced March 2012
...41 months would be...
EOS 5D Mark IV
around August 2014
Mooned by a snowy owl......
Just when many of us were celebrating the end of the mirror slap. Moving parts shutter weigh far less than the mirror, and shake is more noticeable?.
No just as CR guy says - because the camera is much lighter than your typical FF DSLR and with a longer lens attached via lens collar and foot, the camera is just hanging in mid air. Normally thats cool on a rock solid 1DX or whatever but somehow on the A7R it's floppin about when the shutter moves. Even the tiniest vibration can muck up a shot with a tele lens.
Mirror slap is not an issue with DSLRs on a tripod due to mirror lock option.
For instance, I highly doubt this new sensor will exceed (or even equal) the dynamic range of the existing 24 MP 1.5x sensor being used across the way. How could it? It's going to have smaller photosites, by definition, so each will get less photons. Do any of you really see a quantum leap in crop sensor performance coming soon from Canon? I don't.
I'd be surprised if Canon's sensors don't move to back-side illumination pretty soon. It's a quantum leap for high-density sensors like the ones used in cell phones, but the benefit would be smaller in a sensor as big as APS-C unless the sensor's resolution were utterly insane. Either way, though, it should improve the SNR, and should compensate somewhat for the shrink in pixel size caused by a resolution increase, though I'm not sure exactly how much.