I have the 35-80 Mk III lens. With that lens, the lens designation inside the filter ring is an adhesive label. Peel off the label. Remove three small screws and the front element lifts out. Here is a quick sample:
As a follow up to discreet, I removed the front element from the 35-105 last week and it didn't work either. It won't focus on anything without the front element.
I had trouble getting the screw lit evenly so I took my Sigma Super 500 DG in hand and fired of a quick 1/128 power burst from either side during the 4 second exposure.
The subject is a mounting scew off a pc motherboard and is about 12mm in length, I am pleased how sharp the final image came out.
I just found this thread and am really impressed.
My question is: how do you know which lens it will work for ?
I have learnt about optics a few years ago but have no knowledge about lens design. The kind of questions like "what is the front element for ?" or "what happens if I remove this or that piece of glass ?" have no clear answer to me.
If I could dig up a crappy lens for a decent price and turn it into a macro, no doubt I would do it. But I would like to understand why and how first
For instance, I would not like to end up with a lens with fix focus distance or which does not focus on anything.
but I'm eyeing a couple on ebay.
