achieving focus

[aleborek]

hey guys, soon i'll be trying some film astrophotography and there is a bigggggggggggg problem..

how can i achieve focus looking at that tiny viewer?

and where are the film fans from sgl?

[pipnina]

hey guys, soon i'll be trying some film astrophotography and there is a bigggggggggggg problem..

how can i achieve focus looking at that tiny viewer?

and where are the film fans from sgl?

When I go to focus my DSLR I point it at either a planet (if there's one around) or a distant light using magnified view on the live view screen.

As far as doing it with a telescope goes... It's probably not too different.

An easier method would be getting a Bahtinov mask, though.

P.s. by "Film fans" do you mean the photographic film? Because I debut that stuff is very popular around here given the large inconveniance it provides in terms of cost and light sensitivity. Although, if you meant something completely different, sorry

    ~pip

[kalasinman]

After shooting with film for.....well, since in my teens, I got a DSLR 2 years back. I still have 127 in the fridge, should throw it out. I'm never going back.

I literally have no idea as to how you could get focused. Mark you focus ring with small divisions, then take a series carefully moving in small increments and noting which is which , get them processed and printed. See what is focused. Wow

Film? Really??

[aleborek]

When I go to focus my DSLR I point it at either a planet (if there's one around) or a distant light using magnified view on the live view screen.

As far as doing it with a telescope goes... It's probably not too different.

An easier method would be getting a Bahtinov mask, though.

P.s. by "Film fans" do you mean the photographic film? Because I debut that stuff is very popular around here given the large inconveniance it provides in terms of cost and light sensitivity. Although, if you meant something completely different, sorry

    ~pip

yeaa i mean the photographic ones but thanks anyway

[aleborek]

After shooting with film for.....well, since in my teens, I got a DSLR 2 years back. I still have 127 in the fridge, should throw it out. I'm never going back.

I literally have no idea as to how you could get focused. Mark you focus ring with small divisions, then take a series carefully moving in small increments and noting which is which , get them processed and printed. See what is focused. Wow

Film? Really??

woow, i think i'll have a lot of work to do so thanksssss

and that stuff about the fotons hitting (really hitting) my film makes the photograph a little more real it wont be a interpretation of a dslr, it will be the real reaction there.. i don't know how to explain how i love this ;D

[beamer3.6m]

Why not try to set up an eyepiece which is parfocal.

Buy a parfocal ring and then put the camera in the scope and achieve focus. This might take some practise and trial and error.

Once tue camera is focussed remove it and then put in an eyepiece. Dont move the focusser but instead slide the eyepiece up and down in the focusser until focuss is achieved (I.e. dont tighten the eyepiece in the focusser as it is the eyepiece you will move not the focusser).

When you have found it tighten the parfocal ring around the eyepiece (this stops it slipping into the tube) and voila.

Some scopes may not allow this to jave happen but parfocal ring is about £2 on astroboot. The only real issue is achieving the initial focus with the camera but a bright object will help as the view finder can then used.

[kalasinman]

woow, i think i'll have a lot of work to do so thanksssss

and that stuff about the fotons hitting (really hitting) my film makes the photograph a little more real it wont be a interpretation of a dslr, it will be the real reaction there.. i don't know how to explain how i love this ;D

I used to feel just the same BEFORE I got a DSLR. There is logically no difference between recording photon hits with a chemical and a photo site. In either case an accumulation of photons is required to produce any data, and in either case ones eye is not able to directly register the data without some form of accumulation and conversion.

It is significant that professional astronomers were among the first to abandon photographic plates in favor of the CCD.

If you are serious about this, read this first  https://en.wikipedia.org/wiki/Photographic_hypersensitization  A requirement for long exposure photos.

Film is expensive at times hard to find (increasingly so), requires refrigeration. Processing yourself is the only way to assure results . Home processing is expensive and requires toxic chemicals.

Shooting film one often averages one keeper out of 10 attempts.

You never know what you've got until after the event.

Both film and prints degrade over time and use a lot of space to store.

I am unaware that image stacking is possible with film. Total integration times common with DSOs exceed several hours. I'm not aware of any affordable mount which would support accurate several hour exposures, and the highlights would be over exposed if there were a way.

I know I've not covered it all here, but those old timers around who were doing astro with film aren't now.

[Alien 13]

The key to getting focus with a DSLR is getting the liveview screen to work in you favor.

For focussing set ISO high shutter to 30 sec and look for stars on the screen the focus has to be reasonably close to see any but once you find one adjust focus again and zoom in at x10 and repeat.

For the final focus look for a DIM star in the fov that is away from the center and focus again it should be possible (you might have to reduce the ISO at this point) to get the star to blink on/off with the slightest movement of the  focusser.

That should get you as good as any bat mask or software can achieve probably better if the lens/scope has any CA.

Alan

[beamer3.6m]

This is about imaging with film. I assume that a camera with live view will be a dslr not a slr film camera.

[Alien 13]

My bad I saw the title and the Rebel T5i listed in the sig appologies.

Alan

[michael8554]

I seem to remember a knife-edge device being fitted onto the film rails with the camera back open, to get focus.

I googled and found this link:

http://www.howardedin.com/articles/knife-edge.html

Hope this helps

Michael