January 26, 2015, 07:43:51 AM

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Messages - jrista

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1
Derp. Seems these are 5-ink "business line" printers, not photographic printers. Canon really needs to separate out their lines of printers better...imagePrograf always makes it sound like these are photographic printers, when not all of them are.


Guess Epson's still at the top of the list...

2
EOS Bodies / Re: Global Shutter Coming to Canon DSLRs? [CR1]
« on: January 22, 2015, 01:24:33 PM »
Would this allow to sync flash at any shutter speed if we have a flash trigger that is quick enough?


There is no reason why not. Would be very interesting if they did...the trend lately seems to have been to reduce the sync speed instead of increase it, which has been disappointing.

3
Wow. I've been looking to get a 24" large format printer for a while. I keep looking at older models of Canon and Epson wide formats....but at less than $1300, the iPF670 is a steal. O_o

4
Animal Kingdom / Re: Show your Bird Portraits
« on: January 19, 2015, 02:29:44 PM »
Excellent shots lately, Jack! You have improved by leaps and bounds since you first started last year. LEAPS and bounds. Your chickadee shots are better than anything I've taken. Love that first in flight one...superb!

5
Landscape / Re: Deep Sky Astrophotography
« on: January 19, 2015, 02:28:10 PM »
Great images, guys! I'm glad to see some of you are getting into astrophotography. :) It's a great hobby, especially if your an insomniac like me. :P


nightclicks, excellent results with M42 there. You managed to pull out some of the faint outer dust, which is really quite a challenge. You must have some decently dark skies to do that.

6
Landscape / Re: Deep Sky Astrophotography
« on: January 12, 2015, 06:21:06 PM »
Yeah, I've been having a lot of problems with DSS comet stacking as well. I found a PDF recently that explained a specific imaging procedure. The guy was imaging with a mono CCD with color filters, so his sequencing was complex. The trick was to use 20-second gaps between frames to ensure that stars were fully separated from each other. That is the only way that DSS will be able to properly apply kappa sigma clipping to reject stars when it registers on the comet. Anything else, and you'll have problems.


I've been integrating with PixInsight, and have had largely the same problem as with DSS. I think the star-gap technique is the right way to image a comet. If I get another change, I'll be employing it.

Ah interesting.  Since I took 130x20sec subs, I can use every other one that passes a decent score and see how that works.  That gives me a 21 second gap between subs.  Surely I can get at least 40 subs still.

So one of the issues I a see with pixinsight comet integration is that it assumes all subs are taken without moving the field of view.  That is you specify where the comet is on the first and last subs and it interpolates the position on every other sub.  I guess you have to do a star align on every sub first to normalize the fov then do comet integration.


Yes, generally that's how comet imaging works. Most things assume that (DSS does for it's default integration, where you only mark the comet in the first and last subs sorted by time index.) If you change the field between subs, then your on your own. :P

7
EOS Bodies / Re: Speculate: How much noise improvement from 5D3 to 5D4?
« on: January 12, 2015, 01:18:23 AM »
Silly topic IMHO. Why people are so obsessed with noise is beyond me. I notice its mainly from amateurs who have never shot film. Everyone wants to shoot at ISO 25600 and want it to look like
ISO 100. I dont get it. Get over it people.


Actually, you have that backwards. We want to shoot at ISO 100 and not have it look like ISO 800. ;P That is the primary issue with Canon sensors...the noise ramps up as you get to LOWER ISO settings. ISO 100 has aroun 1.5-2x more read noise than ISO 200, which in turn has 1.5-2x more read noise than ISO 400, etc. That flattens the DR curve out, WASTING information that the sensor actually gathered and could otherwise be usable.


It's never been about shooting at ISO 25600 and having it look like ISO 100. It's about getting out of ISO 100 what is there to start with. Canon's high frequency, low parallelism, off-die ADC units are throwing away massive amounts of usable information, where as sensors from other brands are preserving 2-8x more information.

8
Landscape / Re: Deep Sky Astrophotography
« on: January 12, 2015, 01:13:36 AM »
Yeah, I've been having a lot of problems with DSS comet stacking as well. I found a PDF recently that explained a specific imaging procedure. The guy was imaging with a mono CCD with color filters, so his sequencing was complex. The trick was to use 20-second gaps between frames to ensure that stars were fully separated from each other. That is the only way that DSS will be able to properly apply kappa sigma clipping to reject stars when it registers on the comet. Anything else, and you'll have problems.


I've been integrating with PixInsight, and have had largely the same problem as with DSS. I think the star-gap technique is the right way to image a comet. If I get another change, I'll be employing it.

9
Landscape / Re: Deep Sky Astrophotography
« on: January 11, 2015, 04:26:11 PM »
Seems that no matter what I do with DSS and the post in PS, this is the best I can get.  By the time I work through the repetative curve process, the background ends up looking like 16 shades of grey.  I know there is nice data here to be had but it's not coming out with the old school tools.

So I just submitted my trial license for pixinsight before I get too discouraged and give up.


PixInsights calibration, registration, and integration tools are far better than DSS. The registration is far superior, and it includes a CometRegistration tool. I recommend following this:


http://harrysastroshed.com/pixinsight/pixinsight%20video%20files/2013%20pix%20vids/cometstack2/cometstack2.mp4

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EOS Bodies / Re: High Megapixel Camera Coming in 2015 [CR3]
« on: January 11, 2015, 04:19:26 PM »
If that is the case why SONY made a7S? They could stick to a7 and even more to a7R and that's it!


The A7s has more advanced in-camera noise reduction. Exmor is a good sensor, but it wasn't good enough to produce ISO 400k with the low noise levels that the A7s has. The Bionz X DSP is responsible for reducing the noise in each pixel as they are read out. Not much different than what Canon is doing now with DIGIC 6 in the 7D II. If it were not for the more advanced in-camera NR, I would agree...the A7r when downsampled to 12mp would have probably looked very similar to the A7s, primary difference being the downsampled A7r image would be sharper.
So in A7s they... "cook" the raw files?  :o


They do, just as much as Canon "cooks" the RAW files in the 7D II with DIGIC 6. ;P Everyone's cooking pixels today, it's all the rage.
In that case they should be able to "cook"  ;D the A7II files even better since the later camera is newer...


They probably are. The big problem with Sony files is the darn compression. I honestly don't understand that move by Sony, as it wastes so much of the potential of their sensors and their cameras. It doesn't matter to every photo, but enough photos end up with compression artifacts that it's a real bummer. So, regardless of how much Sony cooks their images, I'd say the RAW compression is a vastly more important, and detrimental, issue.

11
EOS Bodies / Re: High Megapixel Camera Coming in 2015 [CR3]
« on: January 11, 2015, 02:26:26 PM »
And in 6 months time, maybe that will be the debate here:

"Canon has more MP, better AF!"
"Sony has more DR, better IQ!"

... but the problem for lots of us will be that a FF sensor that performs the same as the 7D2 sensor won't represent anything new or better: there will be just more of it.

So more DR = better but more MP doesn't? That just betrays your personal preferences. Both can be better, both can be irrelevant, depending on needs.

Quantity (more MP) is not the same as quality (better MP)

You seem to have missed the point of what I said. Better isn't an objective term. For *some* people, having more pixels of even the same quality as today (however you measure it) is better.


+1 I totally agree with this. Not everyone has the same needs. Some people simply need more pixels, others need better pixels. There are certainly options out there if you need better pixels.


It would be nice if you could get both...more AND better pixels...and from Canon (as they do so many other things so well). :P But, that doesn't seem to be in the books...

12
Landscape / Re: Deep Sky Astrophotography
« on: January 11, 2015, 02:23:23 PM »
@lol: Very nice image! You got more tail structure than I did. One thing about imaging comets...they tend to spin, so the tails spin over rather short periods. You might actually get even sharper results by stacking fewer subs, since over the duration you imaged at, the tail was surely spinning (and thus, the relative motion would result in blur when stacked.) But very, very nice image! :)


@Mr Bean, excellent image for a single frame! For sure!


@gruhl28: Great images! I'm glad you managed to get something going on the astro front. It's a fun hobby. Regarding PixInsight...it is a very different kind of program. My  recommendation is, get the trial when you are certain you have the time to take advantage of it. There IS a learning curve. You might want to master some other things first before you dive into PI...however once you DO dive into PI, it without question has some of the most powerful tools available for astrophotographers.

13
Landscape / Re: Deep Sky Astrophotography
« on: January 10, 2015, 05:04:25 PM »
Comet Lovejoy C/2014 Q2


I don't get to do comets often. They aren't in the sky that much, and even when they are, they are often low to the horizon during sunrise. Terry Lovejoy, comet-finder extraordinaire, discovered another comet in August 2014. It finally drifted into the northern horizon skies on December 24th, and I've been wanting to get some comet photons ever since. Finally got a chance last night:





In my haste to get some data before the moon came up, I ended up underexposing my subs. That resulted in the heavy banding of the 5D III showing through. I managed to eliminate most of it, but some is still visible in the coma. This was my first tracked comet image, and I managed to get some detail on the tail, which I'm fairly happy about. Hoping I get another opportunity to image this again, and get some better data.

Really nice.  And very nice you have dark skies!  I'm going to try the 600 tonight but I'm not expecting much.  What was your integration to get this?


This was a really short integration. I had some connectivity problems, so I went with 30x30s ISO 1600 subs. I tried to get 50x45s ISO 800 subs...not sure if they turned out (that data is still on my laptop.) I actually got about 8 to ten galaxies in the frame, at full size. ;)

14
Landscape / Re: Deep Sky Astrophotography
« on: January 10, 2015, 04:05:00 PM »
Comet Lovejoy C/2014 Q2


I don't get to do comets often. They aren't in the sky that much, and even when they are, they are often low to the horizon during sunrise. Terry Lovejoy, comet-finder extraordinaire, discovered another comet in August 2014. It finally drifted into the northern horizon skies on December 24th, and I've been wanting to get some comet photons ever since. Finally got a chance last night:





In my haste to get some data before the moon came up, I ended up underexposing my subs. That resulted in the heavy banding of the 5D III showing through. I managed to eliminate most of it, but some is still visible in the coma. This was my first tracked comet image, and I managed to get some detail on the tail, which I'm fairly happy about. Hoping I get another opportunity to image this again, and get some better data.

15
EOS Bodies / Re: Speculate: How much noise improvement from 5D3 to 5D4?
« on: January 08, 2015, 06:09:35 PM »
I believe ISO 25.6k is not digital, it is still done by an analog amp. It's just an analog amp that is downstream from the pixels. Supposedly that results in less noise. Not sure how, but I gather there are limitations with how much you can amplify the signal with per-pixel amplifiers.


The only truly digital ISO settings (where the adjustment is made AFTER ADC) are the expanded settings, as far as I know.

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