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165 f/2.8 OR 200 f/4 for Pentax 6x7?

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#26 PaulEK

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Posted 11 May 2013 - 11:23 PM

Thanks, Doppler. I think it might cover, too, and the price is good. But it's fairly slow at f/6.6. That would work fine for digital, but would require quite long exposures for film, I expect.

#27 Doppler

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Posted 12 May 2013 - 06:05 AM

I think they make a f4 reducer for it, but that might be pricey.

#28 PaulEK

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Posted 12 May 2013 - 09:18 AM

Yes, and it would also make it about comparable to the 300mm f/4 ED Pentax lens, several of which are up on eBay right now, for prices that are probably less than the total this would come to.

If there was something rare, excellent, and not too expensive up for sale right now somewhere, I'd consider finding a way to pay for it. But I suppose I can wait till I actually get the camera, too!

#29 Nightfly

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Posted 12 May 2013 - 07:01 PM

But then again, the 105 is a great lens for mosaics!!



Posted Image
Milky Way: Three Panel Mosaic by Nightfly Photography, on Flickr

#30 PaulEK

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Posted 12 May 2013 - 09:24 PM

Very nice, Jim!

I noticed a couple of things at the link that raised some questions: First, you said this was done on Fujicolor 100 negative film; can you say something about it? How is it different (better?) than, say Provia 400x? Also, what scanner are you using? And, last, now that I have a 55 and 200, would you think a 105 would be good, for either daylight or astro?

I'm probalby not going to run out of questions very soon, but I won't ask for all of the answers from you.

#31 Nightfly

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Posted 13 May 2013 - 05:28 AM

Hello again Paul. Yea, it was a lazy post. But since you asked. Film. Fujicolor 100 (Superia) is no longer available but I have freezer stock to last a bit. I generally do only a few special runs per year with this film. It is superb in performance yielding high quality images. As a negative film it has the advantage of greater tonality over transparency films and also suffers less halation which gives tiny pinpoint star images. Notice how very delicate details are preserved on the film.

The film is scanned on an Epson V600, stitched and post processed in Photoshop.

The 105 yields a larger field of view and a flat field at f/4.8 allowing wider field mosaics such as this one.

A slightly larger version of the above mosaic can be found here:

https://dl.dropboxus...ch_1280_pix.jpg

This type of work requires very long exposures on the same night. The image above started at the south horizon first and worked my framing up as the night progressed. The three hour of exposure was constantly monitored for aircraft and bright satellites. This is not easy work and I doubt many, if any, will duplicate it. Perfect polar alignment allows the 60 minute exposures at high declinations without field rotation.

I enjoy the challenge and its rewards. The image itself is the ultimate reward and sharing it is a pleasure.

The setup can be viewed here:

http://www.flickr.co...0790621/detail/

I believe this may spark more questions Paul. :roflmao:

#32 PaulEK

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Posted 13 May 2013 - 09:39 AM

The location of your observatory shows that you sure do have very dark skies. I'm not that lucky, but will just have to see how it goes. It's going to be a while, but I'm fairly confident that I'll have a permanent place to mount the G-11 in the next year or so. I'm really looking forward to being able to simply slide open a roof, push a few buttons, and start observing/imaging!

I'll probably have more questions later, but right now, I have to go ship that camera I had up on eBay, to China.

#33 Doppler

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Posted 13 May 2013 - 12:01 PM

The three hour of exposure was constantly monitored for aircraft


Now tell the truth Jim, when was the last time you saw an airplane up there in the middle of nowhere? :ooo: I couldn't resist, living just 60 miles from the Atlanta International.....

#34 Nightfly

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Posted 13 May 2013 - 04:22 PM

:lol:Many would suggest there would be few aircraft, but my view to the south looks over the Atlantic and every aircraft going over the pond to Europe passes my way. Sunday nights are the most quiet and I can let my guard down a bit.

#35 PaulEK

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Posted 14 May 2013 - 12:26 AM

I am very close to the flyway between Minneapolis and Chicago. When I lived in New Mexico, even when I'd drive hours to get between two wilderness areas, high altitude aircraft buzzed by like insects. I think most were military.

#36 Iksobarg

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Posted 28 February 2014 - 03:18 PM

The Pentax SMC 67 200/F4 ($125)arrived two days ago along with a 72mm IDAS P2 filter($300) and the iOptron V2Skytracker($500). I'm chomping at the bit as my wife has now taken them for wrapping as my bday is still a week away. After much research and careful spending I'm looking forward to the this first "tracking" wade into AP. I'm expecting teething pains but thankful for backup of my AP for Beginners book and the good people of this and other forums for help.

#37 Nebhunter

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Posted 03 March 2014 - 08:39 PM

Enjoy, take your time, and awaiting results. If you need any E200 film for the Pentax let me know.

Igor






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