Need Grubb Lens Expertise
I won an apparent Grubb B lens on eBay today - I was looking originally for a Grubb-C Aplanatic Pat. 1857 in order to share acquaintance with one of what Watkins apparently worked with. I looked up information in Vademecum and it seems that this meniscus style lens may have been labelled B even though they were usually labelled C previously? Were the other Bs RRs? What do I have here and from what year? My B lens has serial number 2890 and one sold a while back in another venue and labelled C has serial number 2795, same dimensions as mine (mine is 12" focal length). But, they look like the same lens design to me - see below (mine, labelled B is on the right). Can someone please elucidate? Thank you!
http://i300.photobucket.com/albums/n...dK47/Grubb.jpg
Re: Need Grubb Lens Expertise
I'll browse my literature and come back to you.
Re: Need Grubb Lens Expertise
There has been a previous discussion with illustrations.
It is obvious that the VM's suggestion about the meaning (type of product) of the A B etc is wrong and that there seems to be a connection with size.
I have the same lens as you - labelled A sn 1686.
Many have an additional smaller number(?) after the large letter. Mine looks like A followed by small 6. Main barrel is just over 57mm in diameter.
Re: Need Grubb Lens Expertise
The attached image is from Milan Zahorcak from his ebay listing of the lens.
Dan
Re: Need Grubb Lens Expertise
Thanks guys, any idea what year that serial # puts it at?
Re: Need Grubb Lens Expertise
Dear Richard. This was my answer to you last time you asked me (February last year).
"Check out the recent thread here (December) on Grubb. This objective is identical to the one I have - my serial number is 1686. This is the Dublin period probably 1858/1859. Patent date is 1857 I think. There is no other info available on line."
If some could measure their barrel diameter (like I have done) we might be able to say something about the letter/number code. This includes both the loose washer and the rotary later variation.
Re: Need Grubb Lens Expertise
I have just been in and re-read the VM on Grubb. There are quite a lot of serial numbers and sizes given there and "letters" and focal lengths. Perhaps if aplanatic owners here could do a check of letters/numbers, serial number, focal length and barrel diameter, we could could crack the "Henry Grubb" code?
Re: Need Grubb Lens Expertise
I'll post my information as soon as I get the lens, which is winging over as we read this...
Re: Need Grubb Lens Expertise
Quote:
Originally Posted by
Steven Tribe
I have just been in and re-read the VM on Grubb.
Steven, I went back and reread the December posts and I am more confused than ever...I hope that a few measurements and posts might help here. Seems a bit random to me...:confused:
Re: Need Grubb Lens Expertise
After exhaustive searching, I found ads for Grubb's lens....1883
Dan
PS - I think, like Steven, it has to do with barrel size/depth - flange size??. Here is a nice image of an 'A' model http://www.peterloy.com/_images/gall...97444459-1.jpg