A question about Tiyoda 1x 0.025 objective.

mpan · Post by **mpan** » Sat Oct 10, 2015 6:50 pm

I would like to know if this spring loaded objective can stay fixed at the up position with some sort of push and twist motion or am I supposed to use my fingers to keep it in the up position?

ChrisR · Post by **ChrisR** » Sat Oct 10, 2015 7:24 pm

Do you have a link?

Spring loading is usually for high magnification, short Working Distance objectives, so they do less damage when you crash them into the slide.

mpan · Post by **mpan** » Sat Oct 10, 2015 7:27 pm

there happens to be one similar to mine on ebay...

http://www.ebay.com/itm/SPRING-LOADED-P ... 3d044fa949

ChrisR · Post by **ChrisR** » Sat Oct 10, 2015 7:34 pm

Ah - , the WD of those is very short, because it's hard to make a 200mm focal length lens parfocal on a microscope. So I'm guessing it's the same reason to be sprung. You wouldn't USE the objective with the front pushed in, for any reason.

mpan · Post by **mpan** » Sat Oct 10, 2015 7:57 pm

Thanks for the reply, but I guess I should've been more specific or maybe asked in a different forum? I'm using it on a dslr and Im trying to get the image bigger(the image is in a circle and black fills the rest) and while doing so I've noticed a large improvement when the lens is up. Again, thanks for the reply, because I do intend to use it on my microscope...,but on a dslr do you think there's a way to keep the lens up?

rjlittlefield · Post by **rjlittlefield** » Sat Oct 10, 2015 8:28 pm

There's probably no built-in mechanism for locking the lens up.

No doubt you can add one, using any of several DIY methods involving adhesives and so on.

However...

That lens is designed to be used at 1:1, at effective f/20 (=1/(2*0.025)), and with vanishingly small working distance -- hence the spring.

Used within the frame of a microscope, it provides a valuable service for imaging a field the same diameter as the eyepiece stop.

Used outside the frame of a microscope, it will perform the same service, but suddenly that's a lot less valuable because any ordinary macro lens or repurposed enlarger lens will give the same magnification, with much longer working distance, over the full field of the sensor, and with a wider optimum aperture which implies a sharper image and faster exposures.

So I'm wondering, are you sure you want to jury-rig this lens to do that job?

--Rik

mpan · Post by **mpan** » Sat Oct 10, 2015 8:36 pm

Rik, thanks for the information! I don't plan on altering the lens, well at least not anymore,lol. Thank you all very much for taking the time to help a beginner out!