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Messages - jrista

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61
Animal Kingdom / The 1200mm Sharpness Test
« on: December 07, 2014, 01:05:54 AM »
I started putting together a new bird setup in my back yard a little while back. I haven't had much of a chance to use it yet, but, I did to some shooting at 1200mm f/8+ on the 5D III. At first I was a little dismayed by the sharpness, thinking the 2x TC was really costing me too much detail. However a little bit of tweaking took care of that.

Not the greatest of shots...that day had poor lighting (and it was backlighting), but here is an example of the original shot:



And here is the shot after sharpening (and a little bit of other processing):



Here is a closeup of the original:



And again after sharpening:



The softness present in the original image is pretty much gone after the sharpening. And that's for 1200mm f/10 ISO 1600.

Here is a 100% crop. The lighting, as I said, was horrible...the highlights along the back top of the birds head pushed down the rest of the exposure, and I was already at ISO 1600. So the noise in the background looks bad (I just used LR to denoise, and there is a specific reason why the noise in the background looks so bad...see below...I have other tools that should do a better job, but I haven't bothered yet):



I know a lot of photographers worry about using the 2x TC III on their lenses (one that can take it and still AF, anyway). I don't use it all that often myself, but after seeing how well the detail in this image sharpened up, I am pretty convinced, at least within around 60-80 feet or so, use of the 2x TC need not be accompanied by softer images. It should be noted that I did have to use a fairly high sharpening radius, 2.3 in this case. I normally use much lower radii, 1.0-1.3 tops most of the time. Some times I've even reduced the radius. To fully eliminate the softening, a larger radius was required. One thing that should be noted...the use of a larger radius has a negative effect on noise...it makes noise harder to remove, and sometimes it exhibits artifacts. I think in the long run, for images like this, I'll convert to TIFF, denoise first, then sharpen, which should avoid most of that problem.

62
So, just to make sure I understand here...suddenly a 2-stop DR improvement is now appreciated as the 400% improvement it really is (instead of so little a to be effectively meaningless for most kinds of photography), and is large enough that we cannot achieve it for a reasonable price because products are so "mature"? Hmm...curious...
That´s what puzzles me too ...


Aye...very curious, that...

63
For the recor, a 400% improvement in DR at low ISO can be had for about $3000 in the form of a D810. Also for the record, a 400% improement in DR at high ISO and a 200% improvement at low ISO can be had for about $2500 in the form of an A7s.

Not agreeing with anyone here, but you won't have both in the same body, as you know A7s has 12MPs while D810 36MPs, which is why the A7s has a better high ISO performance, however since both have the same sensor why they don't have the same low ISO performance, maybe its as Roger said in the 7DII Sensor thread, Nikon is doing something with the data to increase the DR.


I don't actually think they have the same sensor. The Exmor in the A7s apparently use the dual CDS approach, which does a preliminary analog CDS then an additional digital CDS. Based on the information I could find, that is not how the Exmors in the D800 series work...they only have Digital CDS. Additionally, I think the A7s is operating at a higher readout frequency, which is probably why it has a bit more read noise and thus the slightly lower low ISO DR. But, it was designed to be a high ISO powerhouse, and having more than two stops additional DR at ISO 51200 over the 1D X is beyond phenomenal...and it still has over 12 stops DR at ISO 100.


Anyway...I was not saying that you could pick up either body and do the same things. What I was saying is you could get the D810 if your primary need is low ISO DR and stills resolution, or you could get the A7s if your primary need was high ISO DR and/or video quality. And you could actually get MORE than a 400% improvement with either camera in terms of DR, and on the D810, you could also get a huge resolution boost as well.

64
Lenses / Re: Review: Sensor Performance of the 7D Mark II
« on: December 06, 2014, 01:56:51 PM »
What would be "game-changing" for me is something like:
* in-vf focus peaking and a evf you cannot tell from ovf
* raw and/or 4k video sub $2k
* open firmware that enables 3rd party addons
One of those is impossible and the other two are features I wouldn't even consider in my purchase decision.
You think an open firmware is impossible?
No, I think an EVF you cannot tell from an OVF is impossible.

Considering the history of technology and what has been deemed impossible, this is a rather courageous statement :-)

No, it's fundamental physics.  An EVF requires dual integration (one for the sensor, one for your eyes).  An OVF does not.


I agree here...I don't think it is possible for an EVF to perform well enough that you couldn't differentiate it from an OVF. Too many things that would push physics too far.

65
Lenses / Re: Review: Sensor Performance of the 7D Mark II
« on: December 06, 2014, 01:10:36 AM »
Sory guys. I'm being really sloppy tinight. Tonight. I have had very servere chronic insomnia for countless years...well over a decade. I go through periods where I just don't sleep for days, and I'm going through one now. After a while, you kind of feel like your drunk, even though your not... The nafter that, if you still haven't slept...yeahhh.......things get really really werid..............

So that's how you have time to do astrophotography?


Heh, sometime. Most of the time, I set up my gear, dila in PA, program an imaging sequene on a target thats just topped the trees, and get guiding going...then start it up aaaaaand....go to bed. :P I've got my gear tuned welll enough these days that it can just do it;s thing on its own now.


I don;t sleep most of the time hen I do that...but at least I'm not up messin around or fretting about the gear/ Spending 5-6 hours in bed is the only rest I usually get. Weekends are uutually the only time I get any actual speep, but according to my sleep studys I don't ever get to stage three...  :(

66
You guys make me laugh, a one stop improvement means twice as good, two stops means four times as good, we are well into product maturity and small incremental increases in performance. What do you think could be done to give you 400% more performance in key areas with a mere 45% price increase?


So, just to make sure I understand here...suddenly a 2-stop DR improvement is now appreciated as the 400% improvement it really is (instead of so little a to be effectively meaningless for most kinds of photography), and is large enough that we cannot achieve it for a reasonable price because products are so "mature"? Hmm...curious...





For everyone here who thinks you need to spend $10k to get better IQ:


For the recor, a 400% improvement in DR at low ISO can be had for about $3000 in the form of a D810. Also for the record, a 400% improement in DR at high ISO and a 200% improvement at low ISO can be had for about $2500 in the form of an A7s.


Just for the record...both productare far cheaper than $10,000, cheaper than the 1D X or 5D III. If you find you actualy have a need for more DR/lower noise at either low ISO or high ISO, you don't need have to spend ten grand. You can spend less than a thir that on the D810, and get one of the best DSLRs on the market that has performance in all areas that is similar to the 5D III. You also have access to one of the best wide lenses on the market, the 14-24 f/2.8. You can spend a quarter and get the best high ISO performance on the market, and get phenomenal 4k video at uunprecedented ISO settings (at least as far as consumer grade products go.)


Just for the record. :P

67
Animal Kingdom / Re: BIRD IN FLIGHT ONLY -- share your BIF photos here
« on: December 06, 2014, 12:48:10 AM »
Canon 7D Mark II with 500 mm lens with 1.4 TC


Nice flight shot! Great pose.


The bird looks slightly soft, though. I assume the 500mm lens is the f/4 L or L II? I'd have expected pinpoint tack sharpness out of that lens and this camera. Out of curiosity...do you know where the lens was focused? I'm just curious, as I've heard a number of reports now about slight softness of fine detail like bird feathers with the 7D II...

68
EOS Bodies - For Stills / Re: Tony wanted to switch to Nikon but Couldn't
« on: December 06, 2014, 12:35:15 AM »
Poor tony. Guy can't get no respect. :P I have a hard time listening to him, he sometime has a halting way of talking that kind of jerk at your years/ But in geneal I think he is a pretty nice guy, even if he isn't the sharpest lens i nthe kit.


s/[sloppywriting]/[goodwriting]/g  :o 8)

69
Lenses / Re: Review: Sensor Performance of the 7D Mark II
« on: December 06, 2014, 12:29:59 AM »
Sory guys. I'm being really sloppy tinight. Tonight. I have had very servere chronic insomnia for countless years...well over a decade. I go through periods where I just don't sleep for days, and I'm going through one now. After a while, you kind of feel like your drunk, even though your not... The nafter that, if you still haven't slept...yeahhh.......things get really really werid..............

70
Lenses / Re: Review: Sensor Performance of the 7D Mark II
« on: December 06, 2014, 12:26:15 AM »
With all the astro talk and the full moon, I thought I'd mention my favorite new astro accessory - the Canon 10x42L IS.  Those things are way better than I ever expected them to be.


Binoculars? That reminds me...I ordered a pair of Oberwerk fully multicoated (even the prisms) 20x80's a while ago...I was hoping they would be here by now...I don't know where they are, or if they were ever shipped. I guess I chould check on that...


IS binoculars must be pretty nice, though. :)

71
Lenses / Re: Review: Sensor Performance of the 7D Mark II
« on: December 06, 2014, 12:24:21 AM »
You cite the Sony ICX sensors in the 0.003 raneg at -10C,; the 7D2 reaches the 0.002 range at -2 C.


That is what the spec usually say on cooled CCD cameras from Atik, QSI, FLI. However, there is anarticle from Craig Stark where he tests an Atik 314L+, and experiences considerably lower dark current of 0.00076e-/s/px:


http://www.stark-labs.com/craig/articles/assets/CCD_SNR3.pdf


At this point, I haven't slept since Monday, so I am not making snense of what he said after that, or why he was measuring 0.0005e-/s/px. Regardles, these are the lowest dark current noise levels I've ever heard of.


The 314L+ uses the Sony ICX285AL, and it has a limited maximum cooling of -27C below ambient. The standard cooling temp of Sony ICX CCDs is usually -10 however unless the ambient temperature was ~62F/17C, I on't even think the temperature of the snesor during his testing would have been that cold...at 65F ambient the sensor would reach it's minimum temperature of around -8C, and at 70 F ambient the sensor would reach a minimum temperature of -6C..

  anyway...whatever I was sayind.....I don't know if the newer ICX674/694/834 sensors can reach that level of dark current...but regardless, when cooled to -10C, the dark current noise is a trivial factor for most common exposure time  I think for an hour long exposure, which you shouldn;t need outside of narrow band oiii filter exposures on certain targets, dark current noise barely tops 3e- at a rate of 0.003e-/s/px. So none of the apers who use the Sony sensors ever bother with any dark frames...many don;t even bother to dither I don't think.

KAF sensors (Now owned by ON semiconductor? Once Truesense, previously owned by Kodak) are definitely not as good. Its really old technology...fdamentaly I dont think it has changed in a very long time, a decade?...it's had minimal improvements, addition of microlenses, maybe a switch to AR glass and really small things like that...but it;s really old tech. So it is not surprising that it does nto have low dark current, and they don't have low read noise either (at best, around 7e- or so, most of the time it;s 10e- or higher) . The reason people still buy them is the sensors can be huge. The KAF-8300 is slightly smaller than APS-C. The KAF-11002 is FF size. The KAF-16803 is a monster 37x37mm square sensor. FLI just released a new camera with the KAF-50100, wich is a 49x37mm 50.1mp behemoth sensor. FLI and On Semiconductor apparently took the old 50100 sensor design, which used to have a mere 25% Q.E., added microlenses and apparently got the Q.E up to around 62%. That puppy is over $20k...so not exactly your hobby camera/ :P

 Anyway...yeah, KAF sensors are very old...old tech, but they are monsters. You could fit 30 of the Atik 314L+ sensors into the area of a single KAF-50100. :P So, maybe not as efficient andg enerally not as goo dfor narrow band imaging...but they make the most beautiful LRGB images tou will ever see.

Ok, sorry...I think that was really sloppy writing, but I am too tired to go back and fix everything... :\

I use several programs for my analyses.  DCRAW and RAWDIGGER for decoding the raw data without changing values. then my own custom code written mostly in Davinci from asu.edu (developed for spacecraft mission imaging data analysis).

I know of RAWDIGGEr, anf I think IRIS uses DCRAW. I was figuring I'd use iris to examin the raw data anyway.

72
Lenses / Re: Review: Sensor Performance of the 7D Mark II
« on: December 05, 2014, 11:24:36 PM »

It should be noted, just for clarity sake, that amp glow is not dark current. Amplifier glow is caused by infrared radiation (radiated heat) from electronics reaching the sensor, behaving like light, and releasing electrons in pixels. It's usually due to inadequate shielding.

Jon, that really isn't plausible.  For Black Body (thermal) radiation at 30 C, the Black Body peak is around 10 microns, and the radiation where the silicon sensor is sensitive (less than 1.1 microns) the radiation is down by a factor of 10^13.  There is also an IR blocking filter over the sensor, blocking another thousand or so.  Thus there simply are not any photons from heat at a wavelength where the sensor is sensitive.  At wavelengths longer than 1.1 microns, silicon becomes transparent and insensitive to light.

Amp glow is due to thermal heating of the sensor, by conduction of heat into the sensor.

Roger


Well, yes, the IR filter would have to be removed, I agree. There was a fairly extensive thread on CN forums a while ago about a 6D self mod that experienced a new source of glow from an external source, but still inside the camera. The assumption was that it was an IR radiation source (as the issue increased with temp), and that the removal of LPF1 and LPF2 allowed radiation from this source to illuminate the sensor, as tests were performed in a pitch dark room, and the sensor was still getting glow from this one source. I actually do not know what wavelength the radiation was...there was no mention, and I guess there were no final concrete conclusions. Whatever it was, restoration of one of the low pass filters eliminated the problem...so perhaps not infrared heat...but infrared light of some wavelength.

73
EOS Bodies - For Stills / Re: Tony wanted to switch to Nikon but Couldn't
« on: December 05, 2014, 05:15:04 PM »
Personally, I would never switch brands. I would just expand my kit. Especially if there is an option to adapt my existing Canon lenses...that makes it easier and cheaper to add something non-Canon to your kit.


I'm considering doing this with the NX1. I still need to see how the testing pans out over the next couple of months, as I am in no rush, but if the camera tests well, and even more so if Samsung releases firmware updates to fix a couple of the known issues with AF in low light, I'd totally add an NX1 to my kit. I'd probably also eventually add some lenses as well.


The same goes for the successor to the A7r...I'd add that as a landscape camera if it fixes a couple annoying things.


But, I wouldn't sell my Canon kit.

74
EOS Bodies / Re: A Real EOS M Replacement Coming Soon? [CR1]
« on: December 05, 2014, 02:32:38 PM »
I am fairly skeptical of a FF EOS-M part coming along any time soon. With Canon's tepid entrance into the market, jumping into it again with another new EF mount (which I think would be required, lenses would have to be designed differently to get the image circle projected large enough to fill a full frame, with minimal vignetting, with the same EF mount) just doesn't seem logical. Not at this stage in the game. I think Canon would need to see growth in APS-C sized EOS-M cameras in the western markets before they, in their conservative ways, move on to make a FF version of EOS-M.


Personally, I'd welcome a better APS-C mirrorless from Canon. APS-C sensors are still relatively large in the grand scheme of things. Overall, they are the third largest general sensor size used in ILC type cameras, second largest if you exclude MFD from the pool. If Canon can improve DPAF, make it super fast, make it track extremely well, work in very low light, maybe even give it some more configurability...along with improved frame rates, IQ, all the standard stuff...oh, and give it a DSLR-style body design (:P)...I think an APS-C EOS-M could be a success in western markets.


I'd be willing to buy a DSLR-styled EOS-M if it had great AF performance and excellent IQ. Let's just say, at a minimum, it would need 7D II/6D level IQ (preferably Exmor/NX1 level IQ) and none of the frustrating CDAF/PDAF funky-hybridized slowness and hunting that seems to occur on current DPAF cameras (or even, for that matter, on Sony A7 series cameras...their AF is decent, but still not on the level of dedicated DSLR PDAF unit performance.)

75
Animal Kingdom / Re: Show your Bird Portraits
« on: December 05, 2014, 02:24:23 PM »
A couple of shots of a very special bird for these parts, a shorelark. Poor light, but a very friendly bird :) (both 700mm, f/5.6, 1/500, ISO 3200)


Really beautiful bird. I love his coloring and patterns. Almost like he has a leaf pattern drawn on his head.

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