Beck 52x / 0.65 reflex objective

[jmc]

I have an interest in UV imaging, so often keep an eye out for useful (or interesting) equipment. Recently I came across an old Beck 52x / 0.65 reflecting objective. This was not with a microscope dealer, and was being sold untested, but for 40GBP I thought I'd give it a go. This is what it looks like.



It is RMS threaded, and you can adjust for both the tube length, and coverglass thickness. When I first mounted it, I got a very blurry image.

Beck still exist, as Beck Optronic Solutions Ltd, here in the UK. And they still make reflex objectives. So I reached out to them for some advice, and they got back to me really quickly which is always a good sign. Once the coverglass thickness and tube length have been set, the mirrors need to be aligned, which is done by adjusting 2 grub screws, while looking through the lens on the microscope. This needs to be done with something called a Silverpoint slide which is a metallised microscope slide which has many tiny pinholes in the region of 0.5 to 5 micron diameter. Mine did not come with this, but they are available separately for 15GBP so I bought one, just to see if my lens could still be aligned. Here is the Silverpoint slide.



It took a few minutes, but following the procedure document Beck provided was straightforward, and I managed to get the lens pretty much aligned (at least good enough for a first attempt at imaging with it). I used the sample pre-prepared slide of a corn seed, and captured a couple of images through the 10x microscope eyepiece. Single images with a camera phone. First with the Beck 52x reflecting objective.



And then with a Zeiss Neofluar 40x objective, which is the nearest magnification standard objective I have.



I must admit, I was a little surprised to get anything, given it was sold untested. I did try stacking with it, but either my stacking technique isn't up to it (very likely), or it doesn't respond well the stacking.

I am hoping to do some UV imaging with this at some point. I measured UV transmission, and it was fairly flat between 280nm and 420nm, which makes me think it'll be useful to try for UV imaging at some point.

For anyone interested here is the link to Becks current range of reflective objectives - http://www.beckoptronic.com/products/re ... bjectives/

[Lou Jost]

Looks really good in the center! Most reports about reflective objectives get results with much less contrast than yours.

Is that with correcting eyepiece?

[jmc]

Looks really good in the center! Most reports about reflective objectives get results with much less contrast than yours.

Is that with correcting eyepiece?

Thanks Lou. Aligning it was critical to getting an image, and for that one of the Silverpoint slides is needed. That might be why a lot of people get softer images, or even nothing at all.

The only eyepiece was the normal 10x viewing eyepiece on my microscope.

[Lou Jost]

You don't mention the brand of scope, so it might or might not be correcting. Usually a correcting eyepiece has a K ion the label.

[rjlittlefield]

This needs to be done with something called a Silverpoint slide which is a metallised microscope slide which has many tiny pinholes in the region of 0.5 to 5 micron diameter. Mine did not come with this, but they are available separately for 15GBP so I bought one, just to see if my lens could still be aligned. Here is the Silverpoint slide.

Can you provide a pointer to where you bought yours? I have interest in getting one for other purposes.

Most reports about reflective objectives get results with much less contrast than yours.

Aligning it was critical to getting an image,

Another cause of low contrast is veiling glare caused by light coming from outside the imaged area. This is much less of a problem with transmitted illumination from a condenser, versus reflected illumination in a typical macro style setup.

--Rik

[jmc]

This needs to be done with something called a Silverpoint slide which is a metallised microscope slide which has many tiny pinholes in the region of 0.5 to 5 micron diameter. Mine did not come with this, but they are available separately for 15GBP so I bought one, just to see if my lens could still be aligned. Here is the Silverpoint slide.

Can you provide a pointer to where you bought yours? I have interest in getting one for other purposes.

Most reports about reflective objectives get results with much less contrast than yours.

Aligning it was critical to getting an image,

Another cause of low contrast is veiling glare caused by light coming from outside the imaged area. This is much less of a problem with transmitted illumination from a condenser, versus reflected illumination in a typical macro style setup.

--Rik

Sure Rik, I got mine direct from Beck Optronic Solutions, in the UK. Website - http://www.beckoptronic.com/ and email address: info@beckoptronic.com

They have been really helpful and I can't praise them enough.

Yes, veiling flare is a big issue with these. I stopped my condenser right down, and had it very close to the underside of the slide for the image above. As you say a big problem for reflected light images.