How do I stop a lens rotating in the lensboard please?

[David Evans]

I bought a Schneider 150mm with lensboard fitted by Robert Whites.
I've since bought a tophat lensboard and lens fitting tool, but now I've changed the lensboard the lens rotates in the board (i.e. it is not a tight enough fit).
I screwed the lens in as tightly as I felt comfortable with going.
Do I need to use more brute force, or is there a 'trick of the trade' to stop this happening?
Thanks fro any advice.

[BarryWilkinson]

David,

New lenses are fitted with a very small screw in the back of the shutter to stop the lens from turning on the lens board. A small hole has to be drilled in the lens board to locate this screw head. Unfortunately most people throw the screw away as it is usually easy to tightened the lens retaining ring sufficiently to stop the lens rotating.

I'm not sure why your lens still rotates? Is the lens board the same thickness as the previous flat board?

If you can't fix it, maybe someone here has a spare screw?

Barry

[IanG]

Sometimes the lens sits on the pin Barry mentions, it should locate in a small cutaway/nick in the board. If this has happened a light jolt may shift the lens which is then not tightened to the board.

Check it if there is a pin and no locator for it a small V notch with a file is all that's needed.

Tighten the retaining ring with a lens wrench, or tap gently with screwdriver & hammer

Ian

[robert.fallis]

Try a little pfp tape that plumbers use, that should tighten it up

bob

[David Evans]

There wasn't a small screw, so that must have been discarded.
I have tightened it a bit further and that actually seems to have done the trick.
The next thing is to make sure I have the tophat (it's an Ebony), which comes in three parts)tight enough to stay firm, but not so tight as to be impossible to undo again. It probably needs some lubricant to avoid this I think.
Anyway main problem solved, so thanks everyone and Christmas Greetings.

[Apple]

David,

Forgive me if I'm barking up the wrong tree but why do you need to put a 150mm lens onto a top-hat lensboard? A standard lens (if you're using 5x4 format) shouldn't have any problem being mounted on a flat lensboard... It's not as though the standards are getting too close to restrict the movement of the bellows etc. I don't need to do that on my Ebony - only if I'm going to short focal lengths like 75mm etc do sunken boards become necessary or over 360mm etc for top hat boards.

Secondly, if you absolutely must use lubricant (most camera 'user-serviceable' threads are assembled dry and the slight tightening 'nip' you can get means the friction will hold things in place), don't use anything liquid based that's classed as 'searching,' i.e. it will creep into cracks and may get into the shutter / lens. This can become an expensive clean-up job if it gets where it shouldn't. For the shutter ring threads, maybe use pencil 'lead' sparingly by 'colouring in' the thread - the graphite is the dry lubricant and it generally stays where it's put - blow off any excess dust when you're done.

Generally, the only problem you might have getting the shutter off the lensboard is if there is some corrosion on the threads but that is a bit extreme unless you've been taking if for a swim or it's been used and abused around humid or salty air - jungles / seaside etc and it hasn't been inspected / wiped over etc later. I've seen one lensboard where the metal on the back of the shutter body and the lensboard had corroded and stuck together. That was an awkward *&*^^ to strip.

Keeping up to a sensible handling procedure will minimise nearly all of the problems you might encounter - the biggest one could be condensation when going from cold areas into warm. Store things in dry conditions and you shouldn't have any issues...

Andrew

[David Evans]

I'd been thinking of graphite (we have some around the house somewhere).
As far as using the tophat lensboard, I got it to be able to get closer focusing without spending money on a macro lens. In every other respect the 150mm worked perfectly with an ordinary lensboard.

[Apple]

I wondered whether you meant macro work once I'd replied

With the 150mm you should be fairly easily able to get 1:1 and a bit more with the standard bellows. Depending upon the top-hat extension, you'll get a bit more but maybe not a lot (an extra 10mm or so won't make much difference unless you're desperate )

I know it's extra dosh but a while back there was a supply of 120mm macro lenses from the States but these were priced very attractively (i.e. cheaply) and snapped up quickly so may be difficult to find. I know a couple on the board managed to get hold of them. These would potentially be better as they're optimised for close-up work but there's nothing wrong with playing with a standard lens to see if it 'floats your boat.'

A wideangle lens could get you more magnification as you'd have more bellows extension available but the light fall-off would be greater (nothing is ever simple in this game ) If you get stuck for exposure calculations, search round the web for the "Quickdisc" - it's a downloadable pdf that you print and cut out and it helps easily work out the magnification factor and exposure increase.

Andrew

[David Evans]

I started out with large format in the spring, and a couple of months after Joanna Carter very kindly showed me how to focus the 'thing' (!) I spent a morning with Lee Chapman in Keswick (Lee is a pro landscape photographer, his photographs are superb, and he was really, really helpful). Lee suggested the tophat to help me capture natural textures in tree bark etc. At this stage 1:1 macro isn't my aim - I'm still getting to know the camera.
I'm at the stage that having tried various focusing hoods I find the bellows type work best for me, with a cloth over the bellows if necessary.
Due to work commitments my free time is short and the weather during the available time seems to have been awful! I had high hopes for this week and it's rained and blown constantly.
I don't take any shots inside, and would need to work out what filter I need to colour balance Velvia if I did.
Out of interest though, which 120mm lenses are macro? I know the Schneider one is, but is the Nikon SW also macro?
I bought a Nikon 90mm SW from the States, saved lots and am really pleased with the lens. Bought a Pentax Spotmeter from US also. Both were internet purchases and very quick delivery and big savings (and I couldn't find them here anyway). The lens came from B&H and looking now they have a lot of LF lenses in stock.
I've also just downloaded the quickdisc - thanks for the tip.
And that's where I'm at really, so all advice is most welcome!
Thanks.

[BarryWilkinson]

The Nikkor macro lens is the 120mm f5.6 AM*ED. As Andrew said, B&H in New York had a 'special' on them a while back. Unfortunately they were all sold some time ago, but they do come up from time to time on the auction site.

Barry

[David Evans]

Thanks Barry.

Do you know how I can calculate the maximum magnification I would get from this lens please?

I've read that 1:1 is achieved where the object distance is twice the focal length of the lens, 1:2 at 1.5 times focal length, 1:3 at 1.33 times focal length, etc. However I don't know how to tie this in to work out the bellows extension needed. I'm not actually clear of what the object is twice the distance from!

I have an Ebony SW45 which has a 190mm maximum bellows extension (that's what Ebony say, and I've just measured it and they are spot on!).

I've just checked with my current 150mm lens on a 35mm tophat board, and reckon I can pretty well fill the ground glass with a 9"x7" image at maximum bellows extension and closest focusing (it's not at all practical focusing at the belows limit though). The film plane to object distance is about 680mm.

With a 150mm lens and 1:2 magnification the object distance should be 225mm. 225mm is actually the bellows and tophat extension, and (I don't know whether what follows is a coincidence) the distance from the lens board to the object is very close to twice that distance at 450mm (225mm + 450mm being pretty close to the 680mm mentioned above).

So presumably with a shorter focal length lens I will get to 1:2 and have some focusing leeway? Using the above I should get 1:2 at 180mm bellows extension, and the object would be 360mm from the lensboard.

I'm not too worried about getting down to 1:1, but would like to get to 1:2 comfortably.

If I really wanted 1:1 I would need to buy a bellows extension, or get a 90mm macro lens (if such a thing exists).

Also can you remember how much B&H were selling these lenses for, so I have a benchmark price if I see one and decide to get it?

Thanks for any advice on this ... very much appreciated.

[BarryWilkinson]

David,

I suspect that there are others here who are more knowledgeable and will give you more acurate answers to your questions?

However I believe all of your assumptions are correct At 1:1 a non -telephoto lens requires a bellows draw of twice the focal length.

For a 1:1 image, this will also be the distance measured from the lens nodal point (where the image inverts) to the object, which for our purposes is near the lens board.

B&H were selling these for $299.95! A lot of people bought them, I suspect, in the hope of making a profit later on? You should also be aware that this lens is really only intended for macro work and just covers 5x7 at 1:1 (@ f22). So unless you want to do a lot of macro work you may be better off using a standard, or slightly wider lens.

Barry

[David Evans]

I'd looked up the details on the lens on the eBaony website and it says it covers 5x7 as you say.
I have Nikon 35mm lenses also, and usually refer to Bjorn Rorslett's website before making a purchase. Surprisingly he says he uses this as a non macro lens on a 6x9 camera. He also uses a 4T filter on it to reduce the need for bellows draw. I hadn't considered doing that.
You've shocked me with the $299 B&H price!!! That's incredible. There's one for sale on eBay at $525 and I was thinking that looked a good deal! I'm not so sure now.
Have a good weekend and New Year.
David

[Joanna Carter]

David, I managed to get one of those 120mm lenses, but not for profit, just because it was too good a price to get a macro lens.

Seeing as you are fairly local, do you fancy getting together, possibly with Andrew and David Pell as well, over the remainder of the holiday, and you can take a look and try out a couple of lenses.

[BarryWilkinson]

David,

Joanna's offer sounds like a good idea. The lens does cover 5x7 but ONLY at 1:1.


Barry