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Ash
20-Sep-2007, 15:56
In a local camera shop there was a brand new in box lens hood for 1, I grabbed the bargain without thinking. In fact, MJ paid the quid for me :D

It's a Hoya (55s) Wide lens hood.

Anyway, the lens I planned it for is the Dagor 180mm f/6,8 that I placed in the Copal shutter (see here (http://www.largeformatphotography.info/forum/showpost.php?p=258039&postcount=1) for pics) but of course the hood itself is oversized and there wouldn't be a filter thread on the lens either.


That's no problem though, I could make a friction clamp to hold the hood in place.


Here's my concern. 180mm isn't THAT long, but considering the size of the hood I'd hope to avoid any vignetting.

Here's the rear of the box,

http://i2.photobucket.com/albums/y43/second-belated/DSC00848-1.jpg

Can I be sure that with the hood fully extended that I will receive adequate shade without any vignetting?

Any idea about my lens options for lf lenses?

Nick_3536
20-Sep-2007, 16:01
Which format is this for?

4x5 set the hood to the "standard" setting.

5x7 set it to wide.

Vignetting check your corners. It's a better shade then no shade.

Ash
20-Sep-2007, 16:02
Sorry I should have mentioned this is for 4x5.

Considering the tiny size of the lens elements on the Dagor, I wasn't sure I'd physically be able to see the lens hood in case of vignetting - I imagine I'd be looking through the corners of the GG, through the lens elements, to the outside with the hood - that's a narrow gap.

Thanks. :)

Ole Tjugen
20-Sep-2007, 21:48
Do it the other way: Look from the front through the lens, and see if you can see the corners of the ground glass. Much easier, less gymnastics needed. :)

Ash
21-Sep-2007, 02:47
Sounds easier to me :D

I haven't yet made any kind of adapter ring, so the hood is sat next to the camera looking useless.

Thing is, the hood is oversized.

The 55 thread and wide-angle shape of the hood is way large for the miniature lens elements on the Dagor - the dagor elements are probably about the size of, say, the elements on an old Rolleicord or Rolleiflex 3,5. Tiny.

That was the idea anyway; I'd have ample shade from light without vignetting, considering the lens size versus hood size. I guess it's try it and see then? :)

Robert Ley
21-Sep-2007, 06:29
See if you can find a step-up filter ring that will either fit on the inside or the outside of your lens and step it to 55mm. That way you can us your hood and put 55mm filters on as well. I did this with one of my lenses that did not have filter threads. I found a 52mm to 67mm ( I have standardized on 67mm for most of my lenses) step up ring that would press fit inside the lens and epoxied it to the lens. Works great and now I can use all of my 67mm filters.
Cheers,
Robert

Ash
21-Sep-2007, 06:45
Thanks Robert - we're on the same page there.

I'm going to be spending a helluva lot on step up/down rings though, trust me. I'd be needing something like 35-40mm all the way to 55mm. I think I have a couple 49-52 sized ones, but I'll go in later to see what can be done.

Lets hope the vintage shop has some cheap filter rings!

Ole Tjugen
21-Sep-2007, 07:22
Ash - if that 180mm Dagor is the same size as the one I have, I'll rummage in my big stack of lens shades and see if I can find two that fit more or less well. If I do, I'll send you one. I think mine is about 32-34mm, just from memory and estimating the distance between two fingers. If you can measure yours,Ii'm sure I have a different lens with the same diameter, anyway!

But that won't be for a couple of weeks yet, since I'm in the middle of the North Sea right now. :(

Steve Hamley
21-Sep-2007, 07:24
Ash,

You're likely to find the Dagor threads are not standard filter/adapter ring sizes. Lenses of this vintage used push-on filter adapters, so that's what you will need to find first. The only other easy solution is to have S.K. Grimes or Tim Sharkey make you one, and that is $$ although a very elegant solution.

The cheapest option is just to shade the lens with your hand, hat, dark slide...

Steve

Ash
21-Sep-2007, 07:40
Ole - Mine is most likely similar to yours. I think it came off of a Strut camera or similar. It's very old. The elements came from a barrel that had a broken focusing helical. 32-ish sounds about right. If you have something that would be great, otherwise I'll simply adapt this huge shade to serve my purposes :)

Steve - no point in paying $$$ for it. I'll make this lens hood fit, don't worry :D

Ash
21-Sep-2007, 08:13
Looks like I'm sorted :D

I was looking for the step-up's that I had previously purchased when I came across a piece of lens barrel. This is the ring/washer that previously held aperture blades in place on a 300mm slr lens I gutted. Fortunate I kept the pieces eh?

There has always been a gap between between the front element and its adapter for the copal shutter, so I utilised that, unscrewing the front and placing this ring/washer between the two.

http://i2.photobucket.com/albums/y43/second-belated/DSC00858-1.jpg

So now all I have to do is place the lens hood over the ring, it sits happily on the lens, by resting behind the ring washer bit. Not too shabby eh?

http://i2.photobucket.com/albums/y43/second-belated/DSC00864.jpg

http://i2.photobucket.com/albums/y43/second-belated/DSC00867a.jpg

It's all non-permanent, the washer can be removed. I could even attach a 55mm filter ring to the ring/washer so that the hood can screw on and have a fully secure fit, rather than simply sit behind the washer.



Through the front of the lens - stood a few inches away from the hood - I can see the corner clips of ground glass fine at all angles. I take it I should be okay for the vignetting I was worried about. I still need to replace the aperture scale on the lens, for now I simply add a stop to whatever it says!

Ash
26-Sep-2007, 13:54
For anybody interested, I have now sorted a filter thread (55mm) on this lens.

I bought a cheap (£5) 70-200mm lens for 35mm. My main intention was to reap the lens elements to experiment with but I noticed it had a 55mm thread on the front. The entire front assembly unscrews so I lifted the rim with the filter thread, placed it behind the ring/washer and screwed in the front element securely. There's a tiny bit of play, but not enough to annoy me I don't think. :)

Collapsed lens-hood:
http://i2.photobucket.com/albums/y43/second-belated/DSC00888a-1.jpg

Extended lens-hood:
http://i2.photobucket.com/albums/y43/second-belated/DSC00889.jpg

The filter thread:
http://i2.photobucket.com/albums/y43/second-belated/DSC00891.jpg

These pics are with a camera-phone with flash, a little grotesque I know.

Comments?