6 replies to this topic

[SMigol]

Over the summer I fell in love with some aerial lenses for large format and got a few of them to try out.

 

I picked up a 900mm f8 Kodak telephoto type 1 and decided to build a camera around it.

 

Saturday night was first light and here is the image taken in the backyard under clear and light polluted skies.

 

M39 at 900 mm by Stephen Migol, on Flickr

 

Here is a tight crop of the central region (this is still a bit larger than 35mm full frame)

Tight crop of M39 by Stephen Migol, on Flickr

 

Why Fomapan?  It's cheap, I had it, and I wanted something that would give me a long exposure without washing out.  This was a test to see if the Losmandy GM8 could handle the heavy setup.  It did, but this was probably an odd situation as the scope was extremely east-biased and so the mesh was very tight.

 

 

[SteveInNZ]

I was going to comment on the quality of the stars in the corners but then I see that the lens is designed for 9x18 !! That's an impressive lump of glass and plenty of room for movements on 4x5.

Looks like a great project.

 

Steve.

[SMigol]

I think the softness in the one corner is due to film flatness.  Or maybe the standard isn't square with the film axis.

 

I tried a shot with the back rotated last night, if the problem follows the rotation, then it'll be localized to the holder or the standard and not the lens.

 

The image circle is huge.  I'm going to modify another lens board and put a 2 inch eyepiece into it so that I can look through it.  

[TxStars]

Hey that is a great start.. 

You will likely need to go vacuum back to keep all of it in focus..

That lens is right on the limit of what the G-8 can swing, better watch out for wind gusts... lol

[SMigol]

I've got a G11 to swap if this proves to be too much for the GM8.  The 8 has the gear box upgrades and bearings etc done a few years ago and has done very well with long exposures and lighter weights.

 

Regarding vacuum back, I've read some threads about modifying holders to make them work this way.  I also have some aero film that's supposedly thin so I may have to suction it flat once I get to cutting it.

[balazs.benei]

Great project, congrats! I really like the results! I wonder how this film deals with Ha regions.

[SteveInNZ]

Great project, congrats! I really like the results! I wonder how this film deals with Ha regions.

The datasheet says it gets up well past Ha but the reciprocity is terrible.

 

Steve.