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Old 29-04-2007, 01:30 PM
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Barb and David

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Arrow Camera Right Angle Finder

We're thinking of getting a 2 X Right angle finder for the viewfinder on our Pentax ist DL camera for DSO imaging.

With the 2 X it would be magnified but would it dim the view too much ???

Any comments appreciated
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Old 29-04-2007, 03:15 PM
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Rigel003 (Graeme)
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I think you'll find that if you want the best focus in your images you'll ultimately need to go for a software solution using your laptop e.g. DSLR Focus or Images Plus. They'll give you a much higher degree of accuracy. I'd put the money towards one of these.
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Old 29-04-2007, 05:39 PM
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In time of film photography, I tried to use right angle finder for my Praktica.. I even built a special microscope for the purpose and it was useful for Moon and bright stars (used with matte glass only, of course,)... However, to find faint objects, right angle finder was totally useless, with or without microscope. I could used it only without any matte glass (as a low power eyepiece), buy then the focussing had to be done earlier (on a bright star).
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Old 29-04-2007, 07:30 PM
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Bard and David

Obviously not Pentax, i use a Canon Right Angle Finder, and wouldn't be with out it, it is brilliant, and i can get sharp focus by eye only 90% of the time.

Never used software ever, i don't think it it's necessary, I'll probably be shot down in flames for this, but what the heck, it works for me.

I cant see why a good Pentax one wouldn't work for you, but as stated before it must be on a Matt Focus Screen

Leon
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Old 29-04-2007, 08:00 PM
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Quote:
Originally Posted by leon View Post
Bard and David

Obviously not Pentax, i use a Canon Right Angle Finder, and wouldn't be with out it, it is brilliant, and i can get sharp focus by eye only 90% of the time.

Never used software ever, i don't think it it's necessary, I'll probably be shot down in flames for this, but what the heck, it works for me.

I cant see why a good Pentax one wouldn't work for you, but as stated before it must be on a Matt Focus Screen

Leon
The Pentax ist DL does have a matt focus screen so a Pentax Right Angle Finder seems like it would be the way to go . Are you talking about a 2 X finder by the way ??

Glad to hear you don't use software Leon we're trying to avoid going down that path also.
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Old 29-04-2007, 08:31 PM
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Bard and Dave,

Please remember i am talking Canon here, i have not used one on a Pentax, however i can't see why it would not be the same.

The Canon has both 2x and 1.4x and can be switched to either while looking through the finder.

Once you have got used to it and found the sweet spot, while looking through it, "so to speak" they are great.

I wouldn't do without mine.

Leon
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Old 29-04-2007, 09:17 PM
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It seems to me that all the responses so far are correct. If focusing faint objects, a lower f-ratio will give a brighter image. However if focusing stars(which are always points) the brightness of the image depends on aperture, not f-ratio or magnification. Bojan's reply seems to make the most sense to me.
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Old 29-04-2007, 10:40 PM
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My best focussing so far has been a simple long exposure, in fine jpeg, with guiding off, and turning the focus dial a couple of graduations every five seconds, "Home made dial graduations" then picking the sharpest part of the trial, and approaching that graduation in the same direction, Seems to be fairly effective and you know what your going to get...you can use the LCD on the camera even if pushed and zoom it...

2 cents..

S
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Old 29-04-2007, 11:17 PM
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Thanks Shawn
Certainly worth a try and will give us an idea of how close we are by the graduations when we focus either way.
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Old 30-04-2007, 12:01 AM
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Good to have your input Bojan, We would be looking at using a 2x finder to focus in on the stars closest to our objects. Our camera has a Matt-11 screen on view finder.
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Old 30-04-2007, 07:23 AM
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Actually everyone here that has responded is basically correct, i think we all do things a little different that suits us and it works, that dosn't mean everyone likes your way of doing things, however at the end of the day we all get that image we like, regardless of what method we use.

Bard and David, i suppose you have to experiment and find what works for you.

Leon
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Old 01-05-2007, 12:04 AM
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I agree with Leon, I love my Canon right angle finder.
Haven't had any experience with the Pentax gear but I assume it works equally well.

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Old 07-05-2007, 12:13 AM
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Quote:
Originally Posted by Rigel003 View Post
I think you'll find that if you want the best focus in your images you'll ultimately need to go for a software solution using your laptop e.g. DSLR Focus or Images Plus. They'll give you a much higher degree of accuracy. I'd put the money towards one of these.
I fully agree with Rigel003.

Had the chance to try all major methods like Finder, Magnifier, Hartmann mask, Knife ede,
PC-Dslrfocus, PC-Imageplus, Zoom into the result screen on the camera,
but if i wanted to be sure to get the "optimum" in Focus,
Notebook plus Software gave me the most accurate focus.
Another good but old solution is the knife-edge method, this was the
best way in the time of analog imaging. As you can
have in digital age the result immediately (without mount and unmount of the DSLR) the knife edge is for me
to cumbersome and oldfashioned.
3rd best solution is to test the sharpness of the stars in the biggest
magnifacation on the DSLR result Screen and comparing smallest starsize with one
older image i have stored on my card which has a perfect focussed
image on it using the same lens or telescope.

To get perfect Focus with DSLR and Finder plus magnifier is in my eperience only luck and very seldom.
The image in the finder look very soon sharp.
But in reality in my case they were are NOT PERFECT SHARP!
It really does not matter if you use a Pentax-, Canon- or Olympus right angle magnifier,
this method cannot compete with the PC-SW method. Also with methods like Hartmann mask
i could not get the accuracy which is needed.

In Internet at pages of different astrophotographer who
do quality images which i admire, i could not find any who do not use the PC for focussing no matter if they
still work with DSLR or with CCD.
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