www.photomacrography.net :: View topic - Not All that Glitters is Gold
www.photomacrography.net Forum Index
An online community dedicated to the practices of photomacrography, close-up and macro photography, and photomicrography.
Photomacrography Front Page Amateurmicrography Front Page
Old Forums/Galleries
 
 FAQFAQ   SearchSearch   MemberlistMemberlist   UsergroupsUsergroups   RegisterRegister 
 ProfileProfile   Log in to check your private messagesLog in to check your private messages   Log inLog in 
Not All that Glitters is Gold
Goto page Previous  1, 2, 3, 4, 5, 6, 7  Next
 
Post new topic   Reply to topic    www.photomacrography.net Forum Index -> Equipment Discussions
View previous topic :: View next topic  
Author Message
Chris S.
Site Admin


Joined: 05 Apr 2009
Posts: 3332
Location: Ohio, USA

PostPosted: Thu Mar 01, 2012 2:50 pm    Post subject: Reply with quote

Rich, either of the lenses you named stand a good chance of working with an infinity-corrected lens intended for a 195mm tube lens.

A bigger question with this bunch of objectives is the working distance. If it's 1.20 or 1.75mm, like the ones g4lab referenced, that would be very short for macro work. My 20x objectives have 10.5mm and 20mm working distance. If one is working only with flat, transparent slides lit from the back (as in the case of much microscopy), no problem. But for typical macro work (front lighting, non-flat subjects), WD's in the range of 1-2mm are highly inconvenient and or perhaps impossible to work with.

--Chris

PS--Is my memory off? The individual lenses have a $55 buy-it-now price. I looked at this auction when Craig first posted the link to it, and thought they were cheaper. Did it change, or am I misremembering?
Back to top
View user's profile Send private message Send e-mail
naturephoto1



Joined: 13 Nov 2011
Posts: 509
Location: Breinigsville, PA

PostPosted: Thu Mar 01, 2012 3:15 pm    Post subject: Reply with quote

Chris S. wrote:
Rich, either of the lenses you named stand a good chance of working with an infinity-corrected lens intended for a 195mm tube lens.

A bigger question with this bunch of objectives is the working distance. If it's 1.20 or 1.75mm, like the ones g4lab referenced, that would be very short for macro work. My 20x objectives have 10.5mm and 20mm working distance. If one is working only with flat, transparent slides lit from the back (as in the case of much microscopy), no problem. But for typical macro work (front lighting, non-flat subjects), WD's in the range of 1-2mm are highly inconvenient and or perhaps impossible to work with.

--Chris

PS--Is my memory off? The individual lenses have a $55 buy-it-now price. I looked at this auction when Craig first posted the link to it, and thought they were cheaper. Did it change, or am I misremembering?


Hi Chris,

Thanks. There are apparently 2 separate listings for the lens, 1 for a single lens and one for a 30 lens lot. That is why many of us have been discussing possibly collectively buying the lot and distributing lenses to the membership. Below are the 2 separate listings:

http://www.ebay.com/itm/200718941277

http://tinyurl.com/6ulyb7m

Rich
_________________
Richard A. Nelridge

http://www.facebook.com/RichardANelridgePhotographer
Back to top
View user's profile Send private message Send e-mail Visit poster's website
Craig Gerard



Joined: 01 May 2010
Posts: 2877
Location: Australia

PostPosted: Thu Mar 01, 2012 3:17 pm    Post subject: Reply with quote

Chris,

The seller has them listed in a box of 30:
http://www.ebay.com/itm/360438163254

and also individually for $54.99 (originally there 109 available)
http://www.ebay.com/itm/200718941277

I asked the seller to perform a simple exercise to determine approximate WD.


Craig

*Just noticed Rich has also responded while I was typing Cool
_________________
To use a classic quote from 'Antz' - "I almost know exactly what I'm doing!"
Back to top
View user's profile Send private message
Chris S.
Site Admin


Joined: 05 Apr 2009
Posts: 3332
Location: Ohio, USA

PostPosted: Thu Mar 01, 2012 3:21 pm    Post subject: Reply with quote

I'm aware that there are two separate listings. My question was about the one first posted--the listing of a single optic. Did that price change?
Back to top
View user's profile Send private message Send e-mail
Craig Gerard



Joined: 01 May 2010
Posts: 2877
Location: Australia

PostPosted: Thu Mar 01, 2012 4:09 pm    Post subject: Reply with quote

Not since I first saw it 24hrs ago.

Craig
_________________
To use a classic quote from 'Antz' - "I almost know exactly what I'm doing!"
Back to top
View user's profile Send private message
Chris S.
Site Admin


Joined: 05 Apr 2009
Posts: 3332
Location: Ohio, USA

PostPosted: Thu Mar 01, 2012 4:16 pm    Post subject: Reply with quote

Pending Craig's getting a response from the vendor, it's an interesting exercise to measure one of the pictures in the vendor's ad. In the analysis below, I've rotated the vendor's picture slightly to square things up with horizontal and vertical. The added lines and notes are mine. The 20mm assumption for the yellow line may be roughly correct if the objective has standard RMS threads.



The approximate 32.5mm length of the green line is interesting. If the lens is standard DIN, it would be set up for 45mm parfocality. A space of 12.5mm between the front of the objective and the subject would suggest a long working distance optic. Given that I'm working with a slightly off-axis photograph--particularly one with in which a bit of bulging glass at the front of the lens might not be seen--and the barrel of the lens is missing, my number could easily be off by a few millimeters from the original working distance with barrel on, the new working distance with barrel off, or both. And again, this is assuming a DIN optic, which it may not be.

Now for another interesting bit. While the current (Mar 01, 2012) JML Website does not list a 20x finite DIN objective--nor any 20x objective with long working distance--the Google cache of February 19 for the JML Website lists two of them, which appear to have since been removed.

Here is the Google cache for the JML page as of about two weeks ago:




Here is the JMP page as of today:




It's intriguing that a number of optics have apparently been delisted from the JML site, right around the time that a major vendor lists a boatload of hemi-demi-semi-similar optics for sale, with the barrels removed. Could these be the apparently discontinued finite 20x 0.30 LWD? Arguing against it would be the seemingly large difference between my measured 12.5 apparent WD and the 5.8 WD claimed by JML. I'm probably off, but by that much? Did JML make an 20x with even longer working distance, which might have been discontinued even earlier?

Just noodling. I'm not interested in buying any of these, but a mystery is always fun.

--Chris
Back to top
View user's profile Send private message Send e-mail
canonian



Joined: 31 Aug 2010
Posts: 890
Location: Rotterdam, Netherlands

PostPosted: Thu Mar 01, 2012 4:31 pm    Post subject: Reply with quote

Interesting!
After reading Chris S. assumptions I'm all ears and eyes on this topic, a 20X LWD would nicely fill the gap in my photo-optics.
_________________
Fred
Canonian@Flickr
Back to top
View user's profile Send private message Visit poster's website
g4lab



Joined: 23 May 2008
Posts: 1434

PostPosted: Thu Mar 01, 2012 5:29 pm    Post subject: Reply with quote

Just to thicken the plot a little note that the seller "sunnking" is in Rochester New York. As is JML. Who probably surpluses everything to sunnking.I betcha.

I'll make a couple of phone calls tomorrow.
Back to top
View user's profile Send private message
Will Milne



Joined: 23 Sep 2008
Posts: 82
Location: Manitoba Canada

PostPosted: Thu Mar 01, 2012 5:35 pm    Post subject: Reply with quote

Isn't an NA of 0.3 for the possible LWD or even the NA of 0.4 for the possible regular WD 20x version mediocre at best? I suspect that there is a silent hope that this JML inherits the same CA free character of the 21 f3.5 but with those potentially low NA values it might also inherit the same borderline sharpness compared to alternatives?

Will
Back to top
View user's profile Send private message Visit poster's website
ChrisR
Site Admin


Joined: 14 Mar 2009
Posts: 8397
Location: Near London, UK

PostPosted: Thu Mar 01, 2012 5:54 pm    Post subject: Reply with quote

The lens certainly looks like a LWD one of some sort from the front glass diameter.
These 20s have diameters(approx) and WDs as follows:

Code:

                              dia     wd
Nik 20 0.4 160   Mplan        3.7     2.7   
Nik 20 0.4 210    DIC         4.2     2.7 
Nik 20 ELWD 0.4 160   Mplan  10.25   10.5
Unitron 20 ELWD 0.3 160       8.5    ??
Nik 20 SLWD  inf 0.35  CF    16.35   20?
Nik 20 SLWD 210 0.35         16.3    19.9
Nik 20 inf LU 0.5             4.0     2.1
Mit/usmco inf 20 0.40        21.5     lots


Putting a ruler against the computer screen image of Chris S's, that glass would be about 8.2mm diameter.
So a WD something around 8mm could fit for a NA 0.3, if the lens design is similar.
If any of these made it to Europe, I'd feel deprived not having one...
Back to top
View user's profile Send private message
ChrisLilley



Joined: 01 May 2010
Posts: 680
Location: Nice, France (I'm British)

PostPosted: Fri Mar 02, 2012 6:35 am    Post subject: Reply with quote

Harold Gough wrote:
I don't know about the value of the lens but that is a very high worldwide mailing charge.


I am seeing US $54.99 for the item plus US $59.72 for postage (and multiple stern warnings tha tthey use UPS only) to which should be added 20% of the total (item plus shipping) sales tax on import plus UPS 'brokerage fee' which is typically at least as much as the tax they paid for you. So probably aroud US$ 150 all in.

The tray of 30 on the other hand has only US $118.26 for postage.

Having someone in the US do a group buy would result in significant saving I suspect.
Back to top
View user's profile Send private message
ChrisLilley



Joined: 01 May 2010
Posts: 680
Location: Nice, France (I'm British)

PostPosted: Fri Mar 02, 2012 6:56 am    Post subject: Reply with quote

naturephoto1 wrote:

The only lenses that I have to the best of my knowledge that I could use as a tube lens would be either my Leica 180mm f3.4 Apo Telyt lens or my Leica 70-210 f4.0 Vario Elmar lens.


Since the 180/3.4 is optimised for use at infinity (and is of excellent quality) , it would probably work very well as a tube lens here.
Back to top
View user's profile Send private message
Peter De Smidt



Joined: 05 Jan 2012
Posts: 233

PostPosted: Fri Mar 02, 2012 7:38 am    Post subject: Reply with quote

If needed, I could help out...
_________________
www.peterdesmidt.com/blog
Back to top
View user's profile Send private message Visit poster's website
conkar



Joined: 18 Dec 2010
Posts: 200
Location: Sweden

PostPosted: Fri Mar 02, 2012 9:37 am    Post subject: Reply with quote

Here is another reference for a 20X JML objective:

Standard Achromatic Microscope Objectives

FL (mm): 9.0
Magnification: 20X with Spring
NA: 0.40
Working Distance: 1.7
Specifications: DIN Type (Shoulder Height 45mm, Mechanical Tube Length 160mm)

http://datasheets.globalspec.com/ps/5225/JMLOpticalIndustries/DFCEF750-DADC-4BC9-9615-8D8971B858B5

When I saw Mr Chris S drawing................. I don't know.....?

Regards,

Conny


Last edited by conkar on Sat Mar 03, 2012 3:35 am; edited 1 time in total
Back to top
View user's profile Send private message Visit poster's website
canonian



Joined: 31 Aug 2010
Posts: 890
Location: Rotterdam, Netherlands

PostPosted: Fri Mar 02, 2012 11:49 am    Post subject: Reply with quote

Conny, I kinda hoped it's the other one:

Standard Achromatic Microscope Objectives -- MSO17900/100

EFL (mm): 8.2
Magnification: 20X (Long Working Distance)
NA: 0.30
Working Distance: 5.8
Specifications: DIN Type (Shoulder Height 45mm, Mechanical Tube Length 160mm)

http://datasheets.globalspec.com/ps/5225/JMLOpticalIndustries/7ADC4F96-68E8-4AB4-B75C-60EB2467DEE7
_________________
Fred
Canonian@Flickr
Back to top
View user's profile Send private message Visit poster's website
Display posts from previous:   
Post new topic   Reply to topic    www.photomacrography.net Forum Index -> Equipment Discussions All times are GMT - 7 Hours
Goto page Previous  1, 2, 3, 4, 5, 6, 7  Next
Page 2 of 7

 
Jump to:  
You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum


Powered by phpBB © 2001, 2005 phpBB Group