[falconeye]

How does the K7 produce 87mb TIFs?

Double-click the raw file and save as TIFF/uncompressed?

I make an experiment:

- RAW (DNG): 14.1 MB
- TIF-uncompressed: 83.0 MB
- TIF-LZW: 90.6 MB (don't ask why Photoshop is dumb enough to blow up the size when compressing ... -- probably going from 24 bit to 32 bit internally).
- TIF-ZIP: 72.6 MB (which is about the size of linear DNG)
- PNG-16bit-lossless: 62.7 MB
- TIF-ZIP-8bit: 15.5 MB
- JPG2000-99%-8bit: 1.48 MB
- JPG-12/12: 6.2 MB
- JPG-6/12: 0.92 MB
- JPG-0/12: 0.33 MB

The number I gave (87MB) was just a quick 14.6MP*48Bit. The exact figure 4672*3104*48Bit yields 87,011,328 B or 83.0 MB.

The actual TIF-uncompressed is 87,041,484 B which is 30,156 B (29.4 kB) larger than the actual pixel data.

To summarize:

A claim of "100 MB image file size" is not very significant if not meant for RAW. But the 645D won't produce 100 MB RAWs, I am pretty sure (would require 50+ MP).

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Last edited by falconeye; 02-16-2010 at 04:46 AM.

[pingflood]

Interesting this photo doesn't have the M.Up button.


ANy commentary on Medium Format Digital for astrophotography?

If you get serious enough about AP to spend anywhere near this kind of coin, you're far more likely to use one of the dedicated, cooled CCD cameras which outperform any DSLR.

[Kenn100D]

https://www.pentaxforums.com/forums/pentax-news-rumors/81538-pentax-645d-user-manual-leak.html

Check last year thread. Must be it. =)

[falconeye]

If you get serious enough about AP to spend anywhere near this kind of coin, you're far more likely to use one of the dedicated, cooled CCD cameras which outperform any DSLR.

Interestingly, Kodak is a major supplier of astro CCD chips, one of them being
http://www.intercon-spacetec.de/fileadmin/user_upload/ics-editoren/download/...0ELongSpec.pdf

So, it is easy to compare KAF-3200ME (astro) and KAF-40000 (MF).

Most strinking diferences:
- much smaller (6.8 µm is almost the same, but only 3.3 MP due to smaller size)
- 8 dB more dynamic range (6 dB is one stop)
- Up to 80% quantum efficiency (but no Bayer color filter!; this is 1 stop better)
- Readout noise 7 e rather than 13 e (if cooled down to 25°C chip temperature, rather than 60°C)

So, I see 2-3 stops advantage for the dedicated cooled astro chip although the base parameters aren't that different.

[pingflood]

Take a look at the KAF-8300 which is one of the more common mid-grade ones -- I am not going to pretend to know how to read the data sheets though.

(edit: these guys make some of the better mid grade gear if you want to peruse specs: http://www.sbig.com/sbwhtmls/online.htm -- I think they're all Kodak sensor based)

[falconeye]

Take a look at the KAF-8300 which is one of the more common mid-grade ones -- I am not going to pretend to know how to read the data sheets though.

I selected the chip I did because I wanted to compare with an interesting candidate.

The KAF-8300 with only 25500 electrons full well capacity, 16 e readout noise, 40% quantum efficiency, and 64.4 dB dynamic range looses (or equals) in every possible category against the KAF-40000 (and 645D should it be using it).

KAF-8300 has at least 1 stop disadvantage against the KAF-40000. And of course, it is only 1/6.7 of its sensor surface ...

Disclaimer: A larger sensor has no noise advantage as such. It is a larger lens/scope diameter (in mm) which brings the noise advantage. I took this into account. Also, only a few astro devices will illuminate an MF image circle; 2" mountings impose (at least) a 1.37x crop to an MF image circle.

[Pentaxian210]

I agree. The silouhette is of a 645D, and nothing else.

[kevinschoenmakers]

Pictures of what the final version may look like:

Pentax 645D - is this the final version? | Photo Rumors

[ozlizard]

Iv'e said it before and that picture prompts, no demands, that I say it again, that is one UGLY camera!

[ogl]

Iv'e said it before and that picture prompts, no demands, that I say it again, that is one UGLY camera!

It's MF baby, it's MF...

[cousinsane]

I believe these pictures have been around for almost a year now.

Pictures of what the final version may look like:

[SteveM]

It's MF baby, it's MF...

You know it!!!....you walk in with one of these puppies and anyone that knows anything about photography from the past few decades will know you mean business (or that you're broke but your really bad pictures are now really big bad pictures )

[Kenn100D]

@ogl,
do you think 645D will be weathersealed??

[ogl]

Maybe. Maybe

[ixian]

645D will be weathersealed??

It would be a pretty much perfect landscape camera then...