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Question from my side. I get an offer for a Derogy Nr.6 brass lens.
The seller knows not really much about it and can´t give me further information.
Nr. 6 means it is for larger sizes >8x10" but which focus length does it has.
The picture he send to me shows it is a Petzval lens and not a later Aplanat lens.
Maybe it is too long for my 8x10"
I want to have a 360 - 480mm lens for portraits. A petzval will be nice.
There are two No.6’s, extra rapid and rapid.
1890’s catalogs
https://largeformatcameras.net/pictu...34/category/20
https://largeformatcameras.net/pictu...33/category/20
1860 catalog
https://cnum.cnam.fr/pgi/fpage.php?M9871/7/100/44/0/0
I don’t have any Derogy but the No.6 may vary depending on the production era.
So if you post the pictures of your candidate petzvals, that would help, especially the front lens opening diameter, focal length, engravings and the serial number.
Thank you for the information.Quote:
Originally Posted by mhayashi
The seller has to send some further information about the size of the lens.
The serial # is 146xx
The dating by Steven is here.
https://www.largeformatphotography.i...=1#post1539027
So the sample would be just before 1870.
The lens has around 360mm focus length and a lens diameter of 86mm. Gives a speed of f/4.2
I want to check it further tomorrow.
Well your sample is not listed in any catalogs above.
If there are any other Derogy catalogs in 1860’s, it may give you an answer.
It might be No.6 bis of Extra rapid based on the 1890’s catalog although not listed and it is not the catalog in 1860’s.
Steven might chime in.
As an opinion, other 360mm-400mm petzval choices for 8x10 would be
Voigtlander No.6 f3.5 before 1878
Dallmeyer 3A f4
and so on…. These are not so hard to find and a bit faster than your candidate.
I already have the lens now and for me it is fast enough. I want to use it with my 8x10" Sinar an the Sinar/Copal shutter.Quote:
Originally Posted by mhayashi
The other lenses are to large in diameter for the shutter, it has only Ø 75mm.
[QUOTE=mhayashi;170368
Steven might chime in.
As an opinion, other 360mm-400mm petzval choices for 8x10 would be
Voigtlander No.6 f3.5 before 1878
Dallmeyer 3A f4
and so on…. These are not so hard to find and a bit faster than your candidate.[/QUOTE]
Sorry, but I am i Spain for the last 2 weeks of January - as usual. Which means I have only recourse to my memory, rather than the printed Word.
Nothing in the focal range you indicate is either Easy to get hold of, will have a friendly Price or Mountable on anything other than a studio camera!
The Derogy is a very good option and the speed is quite adequate.
Personally, I think Voigtlander Euryskops are a better solution for portraits over 36cm - especialy in combination with the Sinar/Copal shutter. Or a Heliar.
My Derogy lens is ready for use. I mount it to a Sinar board in the kind that I can use the Sinar/Copal shutter. For this I have to turn an extension ring between the board and the lens to get the necessary distance.
The lens is a 360mm f/4 or 4,5 lens.
The first test shoots were very poor in quality but I saw that something must be wrong with the lens. The sample shot has wierd sharpness areas.
I have to disample the lens and saw that one of the lenses were wrong mounted.
Now the lens delivers the typical and well known sharpness and image quality which is known of Petzval lenses.
The size of the lens is the max. I want to mount on the front of the Sinar without any additional support. The rear diameter is only a few millimeters larger than the diameter of the Sinar shutter. This makes it perfect for me.
https://live.staticflickr.com/65535/...45e44b7c_c.jpg
The fist sample, you can see that the left side is not sharp and the right side runs out of sharpness as well, I used f/32 and this is not realy ok
https://live.staticflickr.com/65535/...3e37530d_c.jpg
The second test after I turned the lens element, again with f/32. Now it is as aspected. I think a real good lens for its age of over 150 years.
https://live.staticflickr.com/65535/...94756839_c.jpg
Great customization and image confirmation!!