Updated: Canon 18-55mm EF-S is not working, I opened it. I think the EF-S front and read element is too far so basically, you have no working distance.
I'll have a go at shedding some light on why this sort of mod would work, from what I can recall of physics from school:
- A lens will diverge light if it is thicker at the edges than in the middle.
- A lens will converge light if it is thicker in the middle than at the edges.
So, for example, people who are short-sighted need diverging lenses in their spectacles, because their eyes focus too close.
To focus closer, what you need is more converging power, so the elements to remove ought to be diverging elements, i.e. anything that is thicker at the edge than in the middle. From the 18-55 diagram, I would try removing the group that is in front of the rear-most group, if that is possible, as that is a diverging group.
Hi all, I just came across this really interesting thread. Been trying to look up info about reverse macro for quite a while. I'm planning to create a simple reverse macro setup by getting a 52-52 reverse mounting ring. On the body will be a EF 135 F2.8 SF lens, and on the other end, I'm gonna attach a EF 50 F1.8 II. Will this setup result in any vignetting?
going 135-50 shouldn't vignette. It's when you go short to long. Not sure why, optics has sparked an interesting nerve in the noggin lately...
I tried this settup on my 85 1.8, and coupled to a 50 1.4. It works great, auto focus works too, of course only on the attached body lens.
Steve, someone on this thread modded an 18-55 for close focus. Not the fellow with an attached, reversed 50, but someone actually cracked it open. He had some problems getting working room, but got it to work. I suggested though that he look into working the rear portion of the optics, your speculation may be correct. I think that lens works its magic from the rear.
Thanks bellyface.. Appereciate the advice.. i guess I'll give it a try by handholding the lens in front of each other before forking out the cash for the ring and the EF 135..
Couldn't find a cheap 35-80 or similar on ePay Germany, so I ordered a coupling ring to reverse another lens onto my 100mm f/2.8 Macro USM. The day after I placed the order, I got some unexpected money for my work, so I ordered a set of extension rings as well... 8) I should have both in my hands by Wednesday. BTW, the coupling ring (58mm threads) costs just 15 Euros new (from Heliopan).
When I look through my viewfinder, the reversed 50mm f/1.8 vignettes just a little. The reversed 24mm f/2.8 vignettes like crazy, however. I guess I need to couple this approach with an extension ring to get rid of the vignetting. I checked with a ruler last night, and the 100 + reversed 50 gives me nearly 3:1, the reversed 24 goes beyond 5:1. Add extension to get rid of the vignetting, and we're talking about some real magnification...
Since I use a full-frame camera (analog!), your vignetting mileage may vary.
Dang my uncalibrated monitors. At home (15" LCD) the image looks awesome, sharp, contrasty, etc. At work on a 21" flat screen (CRT) it looks very muted, like it needs a boost in saturation or something. Does it look muted to you guys? I can't afford the calibration systems right now so I'm trying to determine which monitor is closer to the "truth" so to speak.
Isaac, LCDs show more accurate colors, CRTs have a bunch of factors that can change your image. Try opening the image in a web browser and photoshop and see them side by side, you'll notice even browsers can show images differently. But I can tell you your photos look amazing!
I have the 35-70 mk1. The front element was screwed on, but it involved some wiggling and some broken plastic, so I'm not sure I was very elegant about it. Earlier in this thread I posted a picture of the disassembled lens. maybe this will help you. maybe it won't. It seems pretty sharp to me for macro use.
