Reverse mounting for MACRO

One of these days I will get the Pentax 100m Macro, but in the meantime I have read on previous threads you can get some pretty good effects reverse mounting the 50mm 1.7 FA.

: Would you, can you do the same with the 50mm 1.4, which I now have (presuming yes) and if so, what accessory/bit do I need to get to reverse mount the lens, as you can tell I have never approached this before!

You can do it with one of these:

http://tinyurl.com/3do68g

Make sure you get one with a 49mm filter thread for the 50mm 1.4.

It enables to focus at a distance of about 6 inches, rather than the normal closest focus of a bit more than a foot. So it's not all that amazing. I think extension tubes are better.

Thx Chris,
Oh, maybe I need to rethink then.

I do have one of these:
Digital High Definition 0.45x wide angle with Macro screw on lens with assort of adaptor rings my OH brought back from USA:




It is pretty good as I did take the image of the feather with it, this is about the max I can get in, screwed onto the front of my 18-55DA
Do you think then that I wd not really improve on what I have already?
Lilly

PS- the feather was about 2" across!

Hi Lilly,

It's very easy to see how close a reversed 50mm lens will get you, just hold it round the wrong way in front of your camera and see what the view through the viewfinder is like. You'll have to set the aperture with the ring on the lens, and have the camera in manual, but you can at least try it and see.

You'll have to move the camera backwards and forwards to focus.

A set of three extension tubes would give you approximately 1:1 magnification with a 50mm lens, but with the result that your subject will be about 25mm from the front of the lens.

Dan

That's how I took this:




It was about 4mm across including legs, and occupied half the original frame width. If the sensor is 24mm wide, that makes the image 12mm wide, so I think that's more like 3:1 than 1:1.

Or have I misunderstood how to calculate the magnification?

I think you've got it right.

No, that would be correct, if the spider was 4mm across it's legs.

However, this is a shot I just took with 3 extension tubes and the 50mm f/1.4...




The width of the image shows about 17mm, so slightly under 1.5:1 magnification. Assuming you have similar sized tubes, either the spider was bigger than you remember (4mm body + legs?), or you have super long tubes, or you have a macro 50mm lens.

I tried reversing the 50mm lens, and got this:




...so much less magnification (less than 1:1.5) than with tubes, as Chris said.

Dan

What about reverse mounting on an other lens. I am still trying to figure out how to calculate the magnification like that.

Reverse mounting a 50mm lens on a 200mm lens equates to roughly 4:1 magnification.

I don't know the exact maths involved but I generally use that as a rough guide.

Reverse mounting a 50mm onto a 70-210mm lens gives a useful variable magnification.

You're absolutely right, my apologies.

I photographed a ruler as you did, focused as close as I could; standard 50mm 1.7 lens, 65mm of tube.

Magnification 1.4, as you say.

I guess the spider was bigger than I thought. It was a money spider - tiny. I guess when I measured its size it must have had its legs much more curled into its body - it is quite stretched out in the photo.

Thanks for the correction. 3:1 did sound a bit unlikely, I must admit.

https://www.pentaxuser.com/forum/viewtopic.php?t=3835&highlight=irb

Lilly, you're on the rocky road to insanity..

need I say more..

Cheers

Liam

Oh Dear ..........thank you for your feedback................I think I might just save up for that 100mm macro !

I have the A-series 100mm macro - you should be aware that its magnification is not as great as the 50mm with extension tubes.




As you can see, the frame shows 4.55 cm of actual distance, so the magnification is only 24/45.5 = about 0.5, compared with 1.4 with the 50mm and the tubes.

I've come by a 28mm Tokina lens with a 49mm filter thread (not bad for £6).

Just stuck that on the reversing adaptor, and here's the result:




It's not at all sharp - I just hand-held it to get this, but as you can see, the magnification is much bigger than with the 50mm lens reversed.

It's about 1.9. So more than the 50mm and the tubes.