August 23, 2014, 12:06:10 AM

Show Posts

This section allows you to view all posts made by this member. Note that you can only see posts made in areas you currently have access to.


Messages - jrista

Pages: 1 ... 100 101 [102] 103 104 ... 265
1516
Third Party Manufacturers / Re: Gura Gear Launches New Color for Bataflae
« 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?

1517
EOS Bodies / Re: Do you have a 4K display?
« on: January 08, 2014, 11:15:54 PM »
From the CNET article:
Quote
Larger 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?

The archaic 24Hz Hollywood standard is changing, as well. The recent Hobbit movies were shot at 48 frames per second. James Cameron is apparently shooting Avatar 2 and 3 (and however many more there may be after that) at 60fps. A 60Hz refresh rate fits well with 240Hz 3D BluRay playback as well. Several cable providers are already clearing bandwidth in order to have more free in order to deliver native content in 4k resolution (and I believe there may already be some 4k content distribution, with 2k downgrade on those channels when 4k isnt' available.) It isn't just TVs that are moving forward into a new era of quality and resolution...the technology used to create and deliver the content we view on them is moving forward as well.

Nay-sayers are simply uneducated as to the big picture. It isn't just 4k TVs that will be playing back ancient Standard HD content (720p). It is 4k TVs that will be playing back native 4k content, from TV and BluRay, as well as internet enabled content delivery networks like NetFlix (which has adopted Super HD for a lot of it's content already, and is also working on preparing their system for delivering 4k content.)

Even assuming one "only" watches 1080p content on a 4k TV. That 2k content is supersampled (more pixels than necessary are rendering it), therefor it still looks better than on a native 2k device.

1518
EOS Bodies / Re: Do you have a 4K display?
« on: January 07, 2014, 10:51:51 PM »
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.

I suspect the industry will be skipping right by "true" LED displays, and heading strait for OLED displays. I don't think there is any way to market a "true" LED display (where there are discrete RGB LEDs for each and every pixel) such that the general public would understand the difference relative to an LED Backlit display (either edge backlit or matrix with local dimming.)

LG already has a 77" OLED TV (although it's curved, a feature I personally am not a fan of...I think it's just a gimmick.) Samsung is supposedly readying an 80" OLED display which features an adjustable curvature (again, a feature I think is a gimmick.)

At 80", standard 1920x1080 pixels are MONSTROUS, and there is no question such large screens could benefit from a factor of four shrink in pixel dimensions. I think 4k will do wonders for these large OLED screens...I just hope they end up flat at some point, as I'd prefer not to have some hulking curved monstrosity popping out of my wall, when the intent is to have a 1" deep beautifully flat monstrosity sitting nearly flush and otherwise inconspicuous.

1519
Landscape / Re: Deep Sky Astrophotography
« on: January 06, 2014, 01:12:48 AM »

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.
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.

Ah, so you are using Registax. Great program! I've tried using my 7D video to image Jupiter...I can't get the same kind of results others get with even just a webcam jury-rigged to a telescope. I think part of it is that the web cams have really tiny pixels which capture enough detail, where as my 7D has pixels that are about 2x - 3x larger...and it's video is pretty crappy.

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!

Yeah, crazy winter indeed. It was around 10°C two days ago. The last couple of days, it's been below zero here in Colorado! Right now it is -26.5°C! :o *shivvvver*  We got about 8-10 inches of snow, the most we've had all winter (previous high was 3"), and it is still snowing. At least we haven't had any freezing rain yet...although I hear the north east region of the US is slated for some nasty freezing rain and sleet, then more sub-zero weather after that, making for some terrible driving conditions.

1520
Landscape / Re: Deep Sky Astrophotography
« on: January 05, 2014, 11:24:15 PM »
Thanks emag, scyrene, lol for your contributions! Great stuff! I'm really feeling the pain of not having a tracking mount. I think I'll pick one up, along with a basic spotting scope, for use with my 600mm lens + 2x TC until I have the chance to buy an actual telescope. I love Celestron's mounts....I might pick up the basic CGEM to start.

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.

I hear PixInsight is pretty good. I also hear good things about Nebulosity. I've read through Nebulosity's manual, it sounds pretty powerful. I'll check out PixInsight next. DSS is an ok tool for being free, but it has it's limitations, and tweaking the final result can be a real pain. A more powerful tool, even if it costs money, would be well worth 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.

Looks great! I'll have to look more into light pollution filters. I live fairly close to Denver, and there can be quite a LOT of light pollution here...so I am not sure if it would really be worth it. At ISO 3200, I can only expose for maybe 10-15 seconds before it really doesn't become any more worth while to expose longer, because the light pollution shifts the entire histogram right (lifts the black level considerably).

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.

1521
Landscape / Re: Deep Sky Astrophotography
« on: January 04, 2014, 07:33:18 PM »
While out at my dark skies site the other day, I also managed to get some wider field milky way shots. I think you can even see some airglow in these photos (the green and red haze in the bottom half):






1522
Landscape / Re: Deep Sky Astrophotography
« on: January 04, 2014, 07:30:36 PM »
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? :)

Glad your finding it inspirational! :) I find the sky to be quite inspiring in and of itself. :D

Regarding larger resolution images, personally, I don't have anything really high resolution. You can find all my work at jonrista.com, and the images there will be a little higher resolution. I downsample them all right now to reduce noise (at full size, they really don't look all that good.) Once I am able to get a tracking mount, I hope to produce MUCH larger and more detailed images, and I'll happily share them. Not sure when that will be, though...few months away at least, if not the end of the year.

1523
Landscape / Re: Deep Sky Astrophotography
« on: January 04, 2014, 07:27:35 PM »
    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.

Hmm! I'll have to check out Astronomik's filters for the supertelephoto lenses. I have the 600/4 L II, which is basically like a good Apochromatic refractor. I have my eye on the Celestron CGEM DX mount, which is about $1200 alone, and it should be able to hold my lens and camera quite easily. Having a light pollution filter would make it a lot easier for me to do some deep sky astrophotography without having to find time to drive an hour or so out of town to find clean dark skies. Thanks for the tip!

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).

Ditto! I'd have been happy with that, too! That is really quite good for just the 135L. I guess I would have gone with a different white balance, but that is a pretty darn nice photo! Out of curiosity...did you use a tracking mount? Signal strength looks pretty good in that shot...a hell of a lot better than I've ever been able to get with my 100mm f/2.8. Stars are nice and round, too...something I've never been able to get without tracking.

1524
Landscape / Re: Deep Sky Astrophotography
« on: January 03, 2014, 03:27:51 PM »
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:



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.

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.
It's -33C here tonight.... I'm not terribly worried about peltier cooling :)

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...

If you have a tracking mount, you should be able to do worlds better than I can with the 60D. You could expose for minutes, which would create a very strong signal. You could then stack, and median averaging or something like Kappa-Sigma clipping in DSS would clean up the noise right away. I think your selling your 60D a bit short. My shots are about as good as I can do with a 7D right now because I lack a tracking mount...if I had one, I guarantee you I'd be making MUCH better shots.

There is no question that a FF sensor would do better, but the problem with the 7D (or any Canon 18mp APS-C body) with non-tracked shots is the fact that they have pitifully low signal and crappy read noise. If you can make the signal strength 100 - 1000 times more powerful, then even Canon's 18mp APS-C bodies will do very well (I've seen a lot of exceptional astrophotography from the lowly rebel series when they are used on tracking mounts.) You should give your 60D another try, and do something like 30x10 minute exposures (five full hours of tracked exposure)...I would bet the results would blow anything I've posted here WAY out of the water.


I have been thinking of getting one of these.... http://focusscientific.com/osCommerce/catalog/product_info.php/cPath/94_47/products_id/649
or
http://focusscientific.com/osCommerce/catalog/product_info.php/cPath/94_47/products_id/650

For a first astrophotography camera, I suspect I'll get the Celestron Nightscape CCD. I've seen some truly amazing images made from it, and it isn't too terribly pricey (around $1500 most of the time.)

The cameras I really want in the long run, though, are these beauties:

QHY11 FF Monochrome

Full frame, 11mp, huge 9µm pixels, monochrome, FWC ~= 6D or 5D III (around 60ke-) with Kodak CCD, read noise ~13e-.

QHY23 Monochrome

APS-C, 9mp, small 3.69µm pixels, supports 2x2 and 4x4 binning (7.38µm and 14.76µm effective pixel sizes), highest Q.E. on the market for an astro CCD @ 77% (visible green, 60% Ha & 70% Violet/Ultraviolet), FWC ~= 7D/60D/Canon 18mp APS-C (around 20ke-) with Sony CCD, read noise ~5e-.

I figure I would want both, depending on the thing I am imaging and how finely I want to delineate detail. Probably years away from getting either...the FF one is $4000, and the cropped one is $3000. :P I am sure the Celestron Nightscape will do in the interim. The one thing that seems strange to me is the readout rate of most CCD astro cameras. The often list the readout rate at Xmegapixels per second, and usually that X is significantly lower than the total megapixels on the sensor. So, for an 11mp sensor with a 1mp/s readout rate, it would take a full 11 seconds to read out the whole sensor. For the 9mp sensor, it would take over 7 seconds to read out the whole sensor. I suspect that has to do with maintaining low read noise...but it was still surprising.

1525
Landscape / Re: Deep Sky Astrophotography
« on: January 02, 2014, 11:12:50 PM »
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:



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.

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.

1526
Landscape / Re: Deep Sky Astrophotography
« on: January 02, 2014, 04:54:24 PM »
Did some more astrophotography last night. Worked on some wide field stuff, using my 100mm f/2.8 macro lens. Managed to get some decent results with stacking, but the 7D's low SNR is really killing me. Here is the axis of nebula in Orion:



From the bottom, you have M42 (Orion Nebula), M43 (De Mairan's Nebula), IC434 (Emission Nebula behind Horse Head), NGC 2024 (Flame Nebula) and M78 (follow the axis of orion, horse head, and flame nebulas up near the top edge, small smudge is a reflection nebula.) This is a stack of 30 frames, each 8 seconds long, ISO 3200.

(NOTE: The noise of the 7D, even after median stacking, is simply too great to eliminate with such short exposures and low signal. I pushed the exposure around as much as I could without making the noise overly apparent, but blah...if you see a lot of it, your screen is to bright!! :P Hope a 5D III (or better, a decent telescope and a peltier-cooled CCD astro camera) finds it's way into my hands sometime in the near future. ;))

1527
EOS Bodies / Re: A 2014 Roadmap Part 1: The 7D Mark II is Coming [CR2]
« on: January 02, 2014, 12:47:21 PM »
what about following (naive fallacy):

EOS 5D Mark II
Introduced November 2008

...41 months...

EOS 5D Mark III
Introduced March 2012

...41 months would be...

EOS 5D Mark IV
around August 2014

???

You are a year early...August 2015. And I think that is a MAYBE. The 5D III is already extremely good. I think Aug. 2015 would be the earliest we might see an announcement for a 5D IV, but I really don't suspect one will actually hit the shelves until sometime 2016.

1528
Animal Kingdom / Re: Show your Bird Portraits
« on: December 30, 2013, 02:09:23 AM »
Mooned by a snowy owl......

Hey man, at least you WERE mooned by a snow owl...they stay completely out of human sight and only moon each other around here... ;P

1529
Third Party Manufacturers / Re: Sony A7R shutter vibration problem?
« on: December 29, 2013, 01:13:56 AM »
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.

Another reason why the "big and bulky" mirror slapping DSLRs still have plenty of life left in them. There will always be something to be said about ergonomics and solidity.

1530
EOS Bodies / Re: A 2014 Roadmap Part 1: The 7D Mark II is Coming [CR2]
« on: December 28, 2013, 07:11:59 PM »
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.

If Canon doesn't move to a 180nm process, moving to BSI on a 500nm process could actually result in fairly significant gains for an APS-C sized sensor. It is absolutely necessary for the tiny form factor sensors in phones and the like these days...hell, some of those sensors might almost be single PIXELs in a larger format sensor given how small they are. :P BSI wouldn't be absolutely necessary for Canon's APS-C, but it would probably offer a greater benefit than for any manufacturers already using 180nm or 90nm processes.

That said...moving to BSI requires a fairly hefty investment in fabs anyway...Canon might as well move to 180nm or a smaller process AND do BSI given the cost necessary to do either one.

Pages: 1 ... 100 101 [102] 103 104 ... 265