[Göran]

Hello my fellow Pentaxians! I have been visiting these forums for a long time now and finally decided to ask for some help. I discovered the world of macro photography and I have a question to ask.

I currently own the Pentax-A 50mm 2.8F Macro lens and use it in conjunction with this extension tube set. My question is: What is necessary to do, to reverse mount the 50mm onto the last extension tube? Is it a 49mm reverse macro ring? I am a bit lost here, hoping for some help.

[UncleVanya]

Yes. You can use the Pentax reversing ring - it will have a 49mm thread on one side and a K mount on the other. This will allow you to reverse it and mount it. You can also do some extreme close ups using two lenses - with one reversed in front of the other using a double sided step ring.

Ideally you may want to add something to the rear of the lens to protect the rear element - an NEX adapter or similar is a potential way to do this. Nikon even made rings that allowed you to mount a filter to the rear of a lens - these can be adapted to Pentax by changing the mount fairly easily.

[Göran]

Thanks for the quick reply. I was also thinking of trying using two lenses, but the only other one I have is the 18-135mm Kit lens. I have no idea how it would perform. The step ring I would use there would be a 62mm(from the 18-135mm) to 49mm(from the 50mm), am I correct?

About the lens being exposed: You are talking about protecting it, while it is not in use, correct? Again, thanks for the help!

[Not a Number]

The Pentax bellows manuals recommend only reversing lens on bellows or tubes if the magnification is greater than 1×. I posted the reasons for this in an early thread. I'll see if I can find it.

[stevebrot]

This is a decent reference:

Reversed lenses

Your 50mm lens reversed onto a 50mm extension tube will provide 2:1 magnification. The same lens mounted reversed without an extension tube will provide 1:1 magnification. Both are significantly higher than your lens mounted directly on the body (1:2). Working distance is usually somewhat better as well.


Steve

[Göran]

The Pentax bellows manuals recommend only reversing lens on bellows or tubes if the magnification is greater than 1×. I posted the reasons for this in an early thread. I'll see if I can find it.

Are you talking about the magnification of the lens alone, or combined with the extension tubes? Because with them it is over 1x

[Racer X 69]

Thanks for the quick reply. I was also thinking of trying using two lenses, but the only other one I have is the 18-135mm Kit lens. I have no idea how it would perform. The step ring I would use there would be a 62mm(from the 18-135mm) to 49mm(from the 50mm), am I correct?

About the lens being exposed: You are talking about protecting it, while it is not in use, correct? Again, thanks for the help!

Not sure how a zoom lens would work with a double lens setup. Also, using newer lenses without aperture rings will make it tough to manage the aperture. You would have to figure out a way to hold the lever that links the diaphragm with the camera to keep it wide open, otherwise the viewfinder will be very dark.

All is not lost though.

Manual lenses can be found at a reasonable cost. Here on the marketplace, eBay, KEH, Craigslist, even second hand stores are all sources available to you.

As for the raw end of a reversed lens, the protection that has been mentioned is for while you are making photographs. When you are done with a photo session you shouldn't be leaving the equipment in the macro set up , but rather break it all down and put everything back, caps, cases, etc.

[Not a Number]

What ever the magnification is with extension.

The Pentax Auto-Bellows A manual with the A-Macro 50mm f/2.8 (set to infinity)
(extension - magnification)
Normal (not reversed)
42mm - 0.8×
47mm - 0.9×
52mm - 1.0×
Reversed
75mm - 1.2×
117mm - 2.0×
169mm - 3.0×

see the below linked post for the reasons to reverse the lens with greater than 1× mag.
M42 adapter - PentaxForums.com

[Göran]

Not sure how a zoom lens would work with a double lens setup. Also, using newer lenses without aperture rings will make it tough to manage the aperture. You would have to figure out a way to hold the lever that links the diaphragm with the camera to keep it wide open, otherwise the viewfinder will be very dark.

All is not lost though.

Manual lenses can be found at a reasonable cost. Here on the marketplace, eBay, KEH, Craigslist, even second hand stores are all sources available to you.

As for the raw end of a reversed lens, the protection that has been mentioned is for while you are making photographs. When you are done with a photo session you shouldn't be leaving the equipment in the macro set up , but rather break it all down and put everything back, caps, cases, etc.

Taking the zoom lens aside for a moment, the 50mm I have is a manual lens and has an aperture ring. My questions then are: Can you provide a link for this type of protection, while shooting? Looking for an NEX Adapter, I couldn't find such a thing. And my last question, my main one that is: Would a 49mm reverse macro ring be enough to mount the 50mm onto the last extension tube? It is not a terribly costly thing to buy, I'm basically hovering over the buy button.

[Racer X 69]

Taking the zoom lens aside for a moment, the 50mm I have is a manual lens and has an aperture ring. My questions then are: Can you provide a link for this type of protection, while shooting? Looking for an NEX Adapter, I couldn't find such a thing. And my last question, my main one that is: Would a 49mm reverse macro ring be enough to mount the 50mm onto the last extension tube? It is not a terribly costly thing to buy, I'm basically hovering over the buy button.

This is the NEX adapter. It adapts Pentax K lenses to the NEX camera. You would be using it as a simple guard for the exposed part of your A lens. Note that you can probably find a real inexpensive one on eBay.

NEX to Pentax K Adapter

Also note that you could probably use an extension tube to do the same thing.

And yes, the reversing ring should get your A 50 to mount to the extension tube(s), and even to the camera without any extension tubes or a bellows.


One of our members here has a great website, Extreme Macro . Everything you ever wanted to know about macro photography can be found there. Check it out. Johan will thank you.


There is some discussion here that may be helpful: Tube Guide

[Göran]

Alright, thanks to you all! I knew this community was awesome from observing the threads I will write an update here once I got the articles I need!
(I think I'll take a cheaper option, not the NEX Adapter linked above )

[Racer X 69]

(I think I'll take a cheaper option, not the NEX Adapter linked above )

eBay

[stevebrot]

Looking for an NEX Adapter, I couldn't find such a thing.

You would be using it as a simple guard for the exposed part of your A lens.

Based on your comments, it appears you already have extension tubes. Use one of those as a "guard" over the rear element of your lens. You should not need a NEX adapter.


Steve

[stevebrot]

Would a 49mm reverse macro ring be enough to mount the 50mm onto the last extension tube?

Yes


Steve

[stevebrot]

...I took a quick cell phone photo of my Pentax-M 50/1.7 reversed with an extension tube on one of my Ricoh film cameras.



Left to right: Ricoh XR7 --> 24mm ext. tube --> 49mm to Pentax-K adapter --> Pentax-M 50/1.7, reversed --> 12mm ext. tube to protect the rear element


Steve