Help needed identifying Petzval style lens

Hi,

I'm new to both this forum and large format photography, so please excuse any newbie language or mistakes.

I have just discovered a vintage brass Petzval style lens that belonged to my grandfather and I need to get some advice on it, so I thought I'd ask the experts! Here are the questions I have, and if any of you can help me in answering them I'd be hugely grateful.


1. What type of lens is this (Petzval, magic lanter etc) and how can I tell?

2. What camera would this be suitable for (full, half, quarter plate etc)?

3. How old would a lens like this be?

4. What sort of price is this kind of lens worth?

5. It was in a pretty grimey condition and I (perhaps foolishly) cleaned it and polished it up a bit. Would this have lessened it's value?


Below is a list of information about it, and I have attached some photos. Hope this helps.

• Brass construction
  
• Lens glass is all clean, and in very condition.
  
• Lens and mounting ring threads are in perfect and smooth working order.
  
• 'Tangent' focusing mechanism is well cleaned and running very smoothly.
  
• 65mm - width at far lens end
  
• 80mm - length (from mounting plate to end of lens when fully extended)
  
• 40mm - front and rear lens glass diameter
  
• 78mm - diameter of mounting plate
  
• 30mm(approx) - aperture/entrance pupil diameter

Attachment 91525

Many thanks! :)

Okay, I will bite (a bit),

Your lens hood looks like it is mounted reversed.

1. Your lens could very well be a Petzval design, it could also be a magic lantern lens. It can be both. None of your images show the upper side of the lens. Is there a horizontal slot, perpendicular to the lens' axis? If there is a slot, it is probably a camera lens. If there is no such slot, it is safe to assume you have a projection lens. Nothing wrong with that.

Try and see whether you can further unscrew the lens groups. For your lens to be a Petzval, one of those should have two glass elements in there, separated by a metal ring. The other group should be a cemented glass pair. If this pair is fixed within its brass casing, that is more evidence that you have a projection lens.

2. That completely depends on the image circle projected by your lens (what type of lens you have and its focal length). There are many threads in this forum on how to roughly establish the focal length of a lens. Judging from your measurements, I am guessing focal length is about 150 mm and f5 at best.

3. From what I see: late 1800's.

4. You mention no maker's name or engravings on the lens. So I am assuming nothing is written on it. Another indicator that this a projection lens. That also makes your lens less collectible. It is impossible to place a value on a lens of an unknown type and focal length.

5. Cleaning is good, polishing an antique brass object generally is not the best move.

Thats is all I can say for now.

Cheers, Maurits

http://www.largeformatphotography.in...17#post1004217

Not much to add to what Maurits writes.
The length of the front/rear cells are unusual. You might consider posting a photo of these cells seen from the "narrow end".
Many of these lenses find good homes with photographers who like to experience the Petzval magic without going for the expensive brand names.
There is a very very small chance that it from before 1860, when the slot system was introduced - but I don't think this is likely.
The refinishing looks very well done, without scratches.
Another sign of a camera lens is that there is a very shallow cut-out inside the edge(s) of the sleeve (the brass tube with the focussing mechanism) which may contain the remainder of the velvet gasket.

Hi,

Many thanks to all you guys who shared your collective wisdom with me about the lens I asked about. Some really useful advice!.

Thanks,

Mrdoodle

And thanks for getting back to us (well, mostly maurits!). Most don't.