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Messages - jrista

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1456
Animal Kingdom / Re: Show your Bird Portraits
« on: May 06, 2014, 11:46:59 AM »
Float tubes - thanks guys  - was thinking an inflatable boat but they are much larger and heavier so this may be a very handy alternative.  Here's a good article: http://flyfish-edmonton.webs.com/floattubing.htm

Jack

I'd still be pretty worried about losing my gear. If I had some kind of floating stand to put the camera on...something very stable that couldn't be swamped, then I might feel safer...but even with a float tube, if I'm just holding my gear.... *shudder*

1457
Third Party Manufacturers / Re: Landscape Filters
« on: May 05, 2014, 10:56:02 PM »
LEE is notorious sold out here in germany.
i heard the LEE ND-GRAD filters are polished on the thighs of virgins .... and there is a shortage of virgins.  ;)

LOL! Well, I guess that's why I have such a hard time finding LEE Grads for sale. :P

I bought into the Lee Filter System a while ago, maybe almost five years ago now. While I will say that it was difficult to buy in, as Lee is perpetually behind on producing enough supply for their demand, their filters are definitely worth it. I've tried other filters, and while quality seems to be improving these days, five years ago it wasn't uncommon to see a marked reduction in IQ when using off-brand filters vs. Lee's filters. They really are a step above the rest in most cases.

I still find that there are filter shortages, Lee filters almost always seem to be sold out, however I now have most of the filters I need, so it's pretty rare that I need another (one case recently would be my broken polarizer...I haven't replaced it yet, it's been out of stock on the relatively rare occasions I look for it.)

1458
EOS Bodies / Re: More Sensor Technology Talk [CR1]
« on: May 05, 2014, 10:13:04 PM »
Welcome.

Re A7R - http://www.sansmirror.com/cameras/a-note-about-camera-reviews/sony-nex-camera-reviews/sony-a7-and-a7r-review.html

Scroll down to "How do they Perform?"

I believe that only applies to their 11-bit "RAW" encoding. That would be something akin to Canon's sRAW and mRAW, not necessarily in encoding, but in lossyness. Neither are actually RAW files, they encode data in a specific way. In Canon's case, the m/sRAW formats are YCb'Cr' formats, or Luminance + Chrominance Blue-Yellow + Chrominance Red-Green. The Y or Luminance channels is stored full resolution, however the Cb and Cr channels are stored "sparse". In Canon's case, all of the stored values are still 14-bit precision, but they do store lower chrominance data. Canon's images would be superior to Sony's, in both that they store more information in total, as well as with a greater bit depth...however both will suffer from the same limitation: The information is not actually RAW, which severely limits your editing latitude.

Generally speaking, the fact that these formats store lower resolution color information doesn't matter all that much. Because of the way our brains process information, if done carefully, a lower resolution chrominance is "missed" in favor of a higher level of detail. YCbCr formats have been around for a long time, since the dawn of color TV even. The Luminance channel was extracted and sent in full detail, while the blue/yellow and red/green channels were sent separately, in a more highly compressed format. This actually allowed color information to be piggybacked on the same signal that "black and white" TV channels were sent on, making it possible for B&W TVs to pick up the same signal as Color TVs.

If you have paid any attention to Canon's video features, you've already heard of similar video compression techniques. You may have heard of 4:1:1, 4:2:2, or 4:4:4. Those numbers refer to the Y, Cb, and Cr channel encoding. A 4:1:1 encoding has full luminance and 1/4 Cb & Cr channels. A 4:2:2 encoding has full luminance and 1/2 Cb and Cr channels.  As you might expect, a 4:4:4 encoding use the same sampling rate for all three channels, and is effectively "full resolution". A standard RAW image is also technically a 4:4:4 R'G'B' image.


1459
Animal Kingdom / Re: Show your Bird Portraits
« on: May 05, 2014, 06:47:17 PM »
Feeding Cardinal

I am actually fairly certain that is a bird with a severely diseased, deformed beak. A few of the house finches each year around here end up with corrupted, diseased beaks like that. It's kind of sad. It usually happens to the birds that become malnourished due to an injury or lost eye during a fight (house finches can get pretty brutal during mating season).

1460
Animal Kingdom / Re: Show your Bird Portraits
« on: May 05, 2014, 06:05:38 PM »
Eldar, funny I was just thinking of buying hip waders for shooting but wondered how safe they are for gear if you stumble??!  Any good stories?

Jack
He he, the advantage of being a flyfisher is that you are used to balance on slippery rocks. Best advice is probably to have a wading stick. That way you always have an extra support on the bottom. I try to not go in too deep though. Luckily I have no fun stories to tell, meaning all my equipment have survived so far ;)

I would strongly recommend wading pants though. You can get fairly good ones fairly cheap.

I wish I could wade in the waters around me. Most of our lakes are part of wetlands, which means they don't have rocky shores or rock covered bottoms...it's all decaying plant matter, which ultimately results in this soft black muck that is several feet deep. Step in it, and at the very least your going to lose your shoe...try to actually walk through it, and you might actually lose yourself as well, and certainly your gear. :\

1461
Animal Kingdom / Re: Show your Bird Portraits
« on: May 05, 2014, 04:56:30 PM »
Beautiful shots, Eldar! That 1D X is a creamy background machine...man, what I would give to have that kind of SNR.

1462
EOS Bodies / Re: More Sensor Technology Talk [CR1]
« on: May 05, 2014, 04:54:22 PM »
(f-ratio doesn't usually matter for planetary, as you image planets by taking videos with thousands of frames for anywhere from a couple minutes to as long as a half hour...then filter, register, and stack the best frames of the video, which is basically performing a superresolution integration...that eliminates blurring from seeing, and effectively allows you to image well beyond the diffraction limit.)

This is very interesting, and news to me. Dare I ask how that is possible? I assumed stacking would take the image to the theoretical best the setup can produce - how does it deal with diffraction? I was using my 500L with extenders to photograph planets using stacking recently, and assumed softness due to diffraction (I was at 4000mm f/40 for Jupiter and 5600mm f/56 for Mars).

There are different ways to stack. The most common is averaging, either basic averaging, weighted-averaging, or sigma-kappa clipping averaging. Those forms of stacking are usually used on star field images, for nebula, galaxies, clusters, to reduce noise (noise is reduced by a factor of SQRT(stackCount)...so stacking 100 frames reduces noise by a factor of 10.)

You can also use "drizzle" stacking and other forms of superresolution stacking. The purpose of these methods is less to reduce noise (although they do help reduce noise), and more to increase detail. Stacking for superresolution aims to chose the best version or versions of any given pixel out of thousands of frames, and sample each pixel in each frame and across frames multiple times with alternate "rotation" factors or something similar. That allows the algorithm to extract the maximum amount of information for each point of your subject.

While diffraction certainly limits your resolution when doing planetary imaging, seeing limits it to a FAR greater degree. The vast majority of blurrieness when doing planetary imaging is due to atmospheric turbulence and poor transparency, by about an order of magnitude compared to diffraction. Stacking thousands of frames with a superresolution algorithm easily cuts through both, assuming you get enough high quality frames. Because these algorithms pick the best version of a pixel and multisample each pixel, you can end up with surprisingly high detail images, despite the effects of seeing and diffraction.

1463
Good timing in Copenhagen

Photo shot with: Canon 6D and Canon 70-200 2.8

https://www.flickr.com/photos/77973666@N06/

Wow. I think we need to redefine what "good" means now...

1464
Software & Accessories / Re: Microfibre Cloths for Lens Cleaning
« on: May 05, 2014, 01:34:05 PM »
Thanks for all the feedback and terrific suggestions. I had no idea this was going to turn into such an interesting topic. I have always just used a microfiber cloth to clean my lenses but am now considering some of the suggestions above.

Btw - what's wrong with putting the microfibre cloth in the washing machine? What happens to it?

When I was collecting crystal whisky glasses I was advised not to dry them with a cloth that had been washed with softener as it, and other chemicals we tend to put in washing machines, can cloud the glass. How this correlates to the glass found on camera lenses I do not know, but I tend to just get new cloths rather than wash them. That said, the guy I was chatting to has never had a problem washing his, in fact he wishes the company were still producing them.

I don't think it's a huge issue but I can see the potential for problems depending on what the cloth is exposed to in the laundry process.  I agree that cloth can retain various chemicals or compounds from a wash process.  If I were to wash an important item like a lens cloth, I would probably just hand wash it so I can control what is introduced to the cloth in the form of dirt or other contaminants from other dirty items, soaps, grit, etc.  All you are trying to do is remove some light oils, dust and light dirt from the cloth anyway.  Woolite or some other delicate detergent would probably work great, then simply hang dry the cloth.  If you've ever held a dryer softener sheet, you will get an idea what is left on clean clothes in the dryer.  Nice for skin maybe but not for leaving smudges on lens glass.

Yeah that's a good point I don't want left over detergent / softner or lint on it plus our washing machine isn't the best at completely removing all that junk! I think I'll just hand wash them from now on. Thanks for the tip!

Washing your cleaning cloths the same way you wash your clothes is a bad idea. Most cloths washing detergents and softeners are explicitly designed to leave behind sent molecules to "freshen" up your clothing. Not all detergent gets rinsed out either, unless you use a doubly-long extended rinse cycle, and even then, your still going to have soap residues in the fabric.

Washing your cleaning cloths with your cloths, or in the same way as your cloths, is a sure way to ruin them. You want very clean cloths, without any residues or detergents or other molecules of any kind.

One of the best ways to clean cleaning cloths is to use activated water. This is water that's been sent through electrolysis, which slightly changes the pH and also created "charge bubbles", electrically charged nodules of water molecules that bond to dirt in a similar way to detergent. Since it's really just water, there is nothing to be left behind.

1465
Diving for Fish

Cherry Creek, a state park, wetland, and nature reserve only a few minutes from my home, has really started to heat up with a whole ton of bird arrivals. Last night, I had a Black-crowned Night Heron practically pose for me, and at one point, he dove off his branch in an attempt to catch a fish. Sadly, the fishcapade was a failure, but I did capture a rather awesome flight shot.

Black-crowned Night Heron
Cottonwood Creek Wetland
Cherry Creek, Colorado

Canon EOS 7D
Canon EF 600mm f/4 L II
Gitzo GT3532LS + Jobu Pro 2




1466
EOS Bodies / Re: More Sensor Technology Talk [CR1]
« on: May 05, 2014, 01:20:46 PM »
Very dangerous, jrista, very dangerous. Astrophotography is like boating - you start out with a $300.00 (slow) toy kayak, you end up wanting an America Cup yacht. I am at the toy kayak stage, and likely to stay there. A combination of living in the center of a "white" zone (central city to the rest of you), having a day job, no longer having the ability to easily adapt to swing schedules, and living in an often cloudy location (St. Louis MO) make serious application to astrophotography difficult. I can learn a bit at our local astronomy park, 45 minutes away in an "orange-soon-to-be-red" zone. High quality darkness is about 2.5 to 3 hours away at minimum.

I know a lot of imagers who shoot under red and white zones. Have you ever looked into a Light Pollution Reduction/Suppression filter? There are a number of them. I'm in a yellow zone myself, but I still use the Astronomik CLS filter myself (I prefer shooting nebula, if you shoot galaxies, lp filters are a mixed bag). You could also look into doing Narrow Band imaging...with NB, you block out a ton of light except the one (or three) very narrow bands your interested in. You need longer exposures, but NB works extremely well under red and white zones, and I've seen some stellar work from people in some of the most heavily populated places in the eastern half of America.

Hats off to you for taking on PixInsight.

PI isn't so bad once you get used to it. It has a funky way of doing things until you learn why...then you realize how incredibly awesome it is. ;) I also recommend it if you image under light polluted skies. It's DBE or Dynamic Background Extraction script can help you extract light pollution from your background skies and flatten it, and can do so if you use LPR filters or not.

I am still drinking the Sigma DP#M koolaid because the color subtlety is very suitable for landscape, and the camera weighs ~300 grams including an aluminum L bracket/grip and can be well supported by a 1600 gram tripod/head/QR kit. Pop some extra batteries, filters, and "nodal" slide in my pocket, and I have a great fast-hiking compatible landscape kit.

For those who understand what Sigma Foveon cameras offer, I say more power to 'em! There is no question the color fidelity is extremely high with Foveon sensors. The light weight is also pretty nice for when you gotta hike to your vistas. That's one of the reasons I like the idea of an A7r for landscape photography...but the camera overall is just...not general purpose enough to justify the cost.

1467
Landscape / Re: hide and seek with the moon
« on: May 05, 2014, 12:15:39 PM »
Ok, I'm sticking to the sticker shock theory ;D. I see what you mean about the non-periodic error that would be an problem. I'll keep looking at my options. This is a very expensive habit hobby >.<.

You have no idea how expensive. :P I have some fairly big aspirations. Just check out the prices on these pieces of equipment:

10Micron GM2000HPS UP
PlaneWave 20" CDK
FLI ProLine PL16803 Mono CCD

That's a semi-pro setup. It's what will allow me to get magazine-quality results, assuming I can find appropriately dark skies and some land to build an observatory under. Those pieces of gear are also on the lower-midrange end of the "high end" market....there are even better mounts, larger telescopes, and even better imagers that cost three to five times more.

So yeah, ridiculously expensive, if you get really really serious. :P

1468
Landscape / Re: hide and seek with the moon
« on: May 05, 2014, 11:58:03 AM »
Yay! more data! Hmm your view on Celestron greatly differs from those at the local astronomy club  :-\. They tend to hold the Advanced VX and CGEM mounts to a pretty high standard. I think it's sticker shock, photographers have already come to terms with $1k tripods and $2k+ lenses. The astronomers in the club haven't quite crossed that bridge yet ;).

Celestron equipment has a very strong religious following. I was hooked on getting a CGEM DX until I started researching, asking questions. Turns out that the CGEM and CGEM DX both have a flawed gearbox that causes what is called the 8/3 error, a non-periodic, non-integer error that is extremely difficult to guide out. I spent over two solid months researching mounts. In the grand scheme of things, my "real" mount will ultimately be the 10Micron GM2000HPS UP, a $24,000 mount which uses in-mount sky modeling and absolute encoding to allow for 20 minutes unguided exposures, and can hold up to 132lb of instrument capacity. :P

In my travels around internet forums during my research, though, I found one very glaring fact: Pretty much NO ONE, EVER, complains about the Orion Atlas or EQ6 mounts. They have about as pristine a reputation as I have ever seen. They are very well loved mounts. This is in great contrast to the fact that you can find dozens, if not hundreds, of complaint threads about the CGEM mounts on astronomy forums all over the net. Mostly about gearbox issues, but not solely. Some Celestron fans and objective mount reviewers will tell you the complaints are not warranted, and perhaps not...but that does not change the fact that the CGEM mounts are widely complained about buy a LOT of people. Statistically, that has to indicate some fundamental issue.

Personally, I LOVE Celestron OTAs. Their EdgeHD scopes are amazing, although they do suffer a bit from the standard SCT problems. If you want an excellent large-aperture OTA, an EdgeHD is definitely a worth while investment. Just...put it on an Atlas, instead of a CGEM. :P

The scope according to the website is about 12lb (I threw it on a scale and it's about right). The 23lb you see includes the metal case it comes with. I know it doesn't change the P2P error, but in terms of load, 120ED + 5D should be ok on the AVX?

If the weight is only 12lb, then it should be OK. I'm not sure what imager your using, if it's a DSLR that could add another pound or so. The guiding setup will add another pound or so, plus don't forget to count the weight of the various cables that you'll need to control everything (cable from the camera to laptop, cable from the guidecam to the mount, cable from the guidecam to laptop, cable from mount to laptop). You might also have additional weight from an extra vixen dovetail and telescope rings (to mount the guidescope to the telescope), which also adds a couple of pounds. Even assuming the scope is 12lb, 50% capacity is only 15lb, and all these accessories are going to put you over that limit.

The AVX is generally not considered a great mount for doing astrophotography. It's great for visual observing, but you have to understand the tolerances involved in astrophotography...if your tracking is off by arcSECONDS, your going to have problems. The AVX is the rock-bottom mount you could possibly get for AP, and it really is insufficient. That assumes that you never, ever plan to use a larger scope in the future...if you do, the $1000 on the AVX is just a waste, as you'll need a larger mount for a larger scope in the future anyway. (You will also quickly find that you'll want a longer scope, much longer, for doing anything other than nebula wide field shots...so something like the 8" EdgeHD or 8" AT8RC, both very cost effective OTAs that produce superb results, would work on an Atlas, they definitely would not work on an AVX.) You would be surprised how much better the Atlas/EQ6 is. Some astrophotographers have loaded it up with 30, 35 pounds of weight and been able to image fine...you would never be able to do that with an AVX.

The price of the Atlas is $1500, so it's $700 more than the AVX. I know that sounds like a lot...but I honestly cannot stress enough how important the mount is for astrophotography. The difference between what is acceptable for visual observing (which is probably what most of your local astronomy club members are doing), and what is acceptable for astrophotography is quite large. You can deal with stars and nebula and planets bouncing around a bit for visual work...even the smallest amount of that is completely unacceptable for astrophotography. If you don't eventually plan on getting a really large OTA that weighs over 50lb, then the Orion Atlas or SkyWatcher EQ6 would probably be the only mount you would ever need...buy it once, never need to replace it or buy a bigger one. The same is not true of the AVX. Your already pushing it's capabilities with your ProED 120.

I guess the cost difference of 900 vs 1500 is peanuts compared to everything else >.<

It really is. The mount is the centerpiece. If your mount isn't up to snuff, then it really doesn't matter what your mounting onto it...your already screwed. :P Big thing to keep in mind, visual is very different, in terms of requirements and what's acceptable, from astrophotography. Local astronomy clubs tend to be based on visual observing, and less on astrophotography, so their advice is likely to be a bit biased.

1469
Animal Kingdom / Re: Show your Bird Portraits
« on: May 05, 2014, 11:50:48 AM »
Long-billed Dowitcher

The Cottonwood Creek area is really starting to heat up. A number of duck species are still hanging around, at this point I suspect for the whole summer. The shorebirds are starting to show up in larger numbers as well. One of my favorites is the Dowitcher, the long-billed dowitcher to be specific. They are one of the more colorful shorebirds, with colorful golden-fringed back feathers and buffy breats, and beautiful streaks around their faces.

Managed to capture a few shots of a trio of dowitchers just at sunset. My vantage point allowed the fresh new greens of spring and the old dried browns of last years growth to produce colorful OOF reflections and blurs, which nicely complimented and contrasted with the bird's own colors.

Long-billed Dowitcher
Cottonwood Creek Wetland
Colorado

Canon EOS 7D
Canon EF 600mm f/4 L II
Gitzo GT3532LS + Jobu Pro 2






1470
Animal Kingdom / Re: Show your Bird Portraits
« on: May 05, 2014, 11:45:54 AM »
Maiaibing, LOVE the color in those shots! So rich!

Radagast, phenomenal detail! Such a beautiful bird.

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