# Reverse prime macro lens



## Dmitri (Apr 16, 2010)

I've been having some fun with this, but the DOF is crazy small... is this normal for macro photography or is it just because I'm cheesing it?


----------



## Derrel (Apr 16, 2010)

Shallow DOF is pretty normal when doing ultra-close or high-magnification photography. it doesn't matter if you have high-quality reversing rings, or are just holding a lens in reverse over the lens mount by hand---the resulting DOF is going to be small.


----------



## Dmitri (Apr 16, 2010)

ok, just making sure. Thanks Derrel


----------



## Dmitri (Apr 16, 2010)

Thats some DOF lol


----------



## Overread (Apr 16, 2010)

Neat money shot !

But yes as Derral said no matter the method you use as magnification goes up the depth of field starts to drop off. You can lower your aperture to counter this, but also note that in most setups as you increase magnification your diffraction limit will also change accordingly. 
Have a look at this set here: MPE 65mm test shot series - a set on Flickr

You can view the fullsized images there and see for yourself how diffraction starts to become more and more of a problem as the magnification goes up. I'd honestly spend an hour or two testing this with your setup(s) just to get an idea of where the new sweetspots for sharpness are


----------



## Dmitri (Apr 16, 2010)

Overread said:


> Neat money shot !







Overread said:


> But yes as Derral said no matter the method you use as magnification goes up the depth of field starts to drop off. You can lower your aperture to counter this, but also note that in most setups as you increase magnification your diffraction limit will also change accordingly.
> Have a look at this set here: MPE 65mm test shot series - a set on Flickr
> 
> You can view the fullsized images there and see for yourself how diffraction starts to become more and more of a problem as the magnification goes up. I'd honestly spend an hour or two testing this with your setup(s) just to get an idea of where the new sweetspots for sharpness are



Well I'm just hand-holding my 50mm backwards, so it's not exactly a "setup"  Just having some fun and wanted to know if the DOF was all macro shots or the fact that I have 0 aperature lol


----------



## Derrel (Apr 16, 2010)

Dmitri--A neat "trick" or workaround with a Canon EOS mount lens used in reverse is to mount the lens on the body normally, and press the camera's depth of field preview button and then remove the lens from the body while continuing to hold the DOF preview button in and the camera still switched to ON. That will keep the lens stopped down! This is the only way for the user to control the aperture of a reverse-mounted Canon EOS lens, or when using those ultra cheap-o aftermarket extension tubes that have no electrical contacts.

Reverse-mounting a lens that has a diaphragm control ring on it, like an older Pentax M42 or K-mount, Nikon F, Minolta MD, Olympus OM, or Canon FD-mount lens (plus others) is pretty straightforward, since all those lens mounts use a mechanical aperture control ring on each and every lens.


----------



## Overread (Apr 16, 2010)

Of course the downside to the stopping down trick is that it makes your viewfinder image much darker since the aperture blades are blocking the light. I tend to use a little single bulb LED torch on a flexi arm to help give a little pinpoint of light to help focus. Indoors (where things are really quite dark) I find it very essential. 

The only other way is to use a Novoflex reverse mount adaptor controler thingy, but unless you find one second hand its price new is very prohibative unless you intend to do a lot of reverse mounted work.


----------



## Derrel (Apr 16, 2010)

If you keep the subject matter perfectly parallel with the back of the camera, you have something like one millimeter's worth of depth of field to play around with. As overread points out, it can be very difficult to see through the camera with the lens stopped down to working aperture, so the small LED flashlight as a focus-assist light makes a huge amount of sense. In the above photo, I could barely see through the stopped-down lens, and ended up shooting ten frames just to get a couple good, sharp shots where the depth of field band was precisely aligned with the penny's surface and the currency's surface, which was about .9mm behind the coin's main surface, give or take.


----------



## Dmitri (Apr 17, 2010)

Holy crap that DOF trick is awesome!!!!

From




To





Overread: Yeah I noticed! lol Between holding the lens up, needing a flash and a light to see f/22 spur of the moment photos may be tough 

Derrel: Great shot of Lincoln-moneys! Thanks for the info and the DOF tip!


----------



## Overread (Apr 17, 2010)

Yep! Though personaly I would try to stick to aperture values wider than f16 - Infact I tend to keep f13 as my main limit because of diffraction. If you start getting much smaller no matter how well you take the shot the overall end result will be noticably softer. I've no idea quite how this changes when you reverse the lens, but it would be interesting to see where the diffration limit is sitting.


----------



## Dmitri (Apr 18, 2010)

Overread said:


> Yep! Though personaly I would try to stick to aperture values wider than f16 - Infact I tend to keep f13 as my main limit because of diffraction. If you start getting much smaller no matter how well you take the shot the overall end result will be noticably softer. I've no idea quite how this changes when you reverse the lens, but it would be interesting to see where the diffration limit is sitting.



Thanks, and I think you're right. I remember reading somewhere that most lenses have f/8 and f/16 as the "sweet spots".


----------



## D-B-J (Apr 18, 2010)

looking good! Yeah, just keep the lens parallel with the subject and you should be all set with your dof, or lackthereof.


----------



## Dmitri (Apr 19, 2010)

ok so another question...

I saw a DIY site that made a pringles tube into a macro lens (attached the 50mm to the end of the tube, and the other end to the camera).

What does the distance do? I plan to rig a contraption to hold the 50mm in place, and want to know whether I should just attach it or toss it on a tube?

Does it magnify more/less the further away?


----------



## Overread (Apr 19, 2010)

The pringles tube is doing the exact same work that an extension tube would be doing. So the same formula for tubes works for the pringles - focal length over tube length - the longer the tube for a set focal length the more magnification you will get.

Using this method you will lose infinty focus and also reduce the minimum focusing distance of the lens (by a large amount) and it is his reduction that allows you to focus closer and thus get a more magnified image.

However with no contacts what so ever between the lens and the camera you again lose your controls over the lens. In addtion remember that the tube will lose you light (For both taking and focusing the shot) and also whilst there is no optical component you will suffer a degree of image quality loss - again the longer the tube the more you will lose.


----------



## Dmitri (Apr 19, 2010)

Overread said:


> The pringles tube is doing the exact same work that an extension tube would be doing. So the same...



I think I understand what you're saying, and I reckon it makes sense. The further my lens from the body, the better the magnification, but the less the image quality. So a trade-off.

It might be worth making an adjustable tube (I would use pvc piping) that can go long or short. 

Thanks for the help, Overread. You're a fountain of info


----------



## Overread (Apr 20, 2010)

An adjustable tube like you describe would be exactly like a bellows setup - infact you might be able to find a cheap old film era set of bellows on a rail on ebay and a cheap adaptor mount to mount it to your camera. Failing that there are some pretty cheap hongkong bellows that you could look into as well.


----------



## eric-holmes (Apr 20, 2010)

When I turn my prime around and hold it against the mount it just blinks "f--"


----------



## Overread (Apr 20, 2010)

You might have to shift into manual mode to get the camera to fire the shutter - regardless you will have to be in that mode to set a decent shutter speed most likley (you will be needing flash for a good exposure as you can't hold the lens perfectly still over a longer exposure). 
1/200sec shutter speed
ISO 100 
and let flash deal with the rest of the needed light.

Also I have a feeling that Nikon lenses always close down to the smallest aperture when removed from a camera body. Further the aperture setting trick does not work on nikon lenses - you have to have one of the kind with manual aperture controls on the lens itself in order to be able to control the blades.


----------



## Dmitri (Apr 25, 2010)

And there's no way to focus the reverse prime other than moving back and forth, right? 

I mean - I'm stuck with one distance, one focus?


----------



## Overread (Apr 25, 2010)

Im sure you could adjust the focus (just turn the lens and the focus should shift) whilst its in the reversed positon. I however have no idea how much or little this will affect your end image.


----------



## Dmitri (Apr 25, 2010)

Overread said:


> Im sure you could adjust the focus (just turn the lens and the focus should shift) whilst its in the reversed positon. I however have no idea how much or little this will affect your end image.



ok I'll keep trying.


----------



## Derrel (Apr 25, 2010)

You can adjust the focus on the lens, but it will not make a huge amount of difference. The primary method of focusing the images is to move the camera closer or farther from the subject. This system does not give you a tremendous amount of flexibility. I see you have a Nikon: I would like to suggest that there is an older accessory, often available pretty cheaply, called a macro converter or sometimes called a macro coupler; it is in effect, a variable-magnification combination telephoto converter AND extension tube, combined into one device. These were popular in the 1970's and into the 1980's their prevalence sort of waned. I have one, and it was made by Panagor. It offers a rotating ring with a magnifcation scale with 1 to 10,5,3,2,1,5, and finally 1:1 (full life-size) image magnification, when using a 50mm lens focused at infinity. It has some lens elements in the middle of about a 25mm or so extension tube-type barrel, and it works quite well. COnstruction quality is typical mid-1970's,meaning rock solid and precision build and silky smooth zooming. It is inscribed with the name Panagor Auto Macro Coupler,and it is a device that I payed $25 for. It's a very useful device for Nikon mount cameras, since it mounts onto all Nikons (the older D100-D50-D70-D200-D80-D90 series bodies, as well as the pro-level bodies that have an AI-tab, like the D1-D2-D3-D300-D700), and maintains automatic diaphragm with any NIkon mount lens made since 1959. it's a **highly desirable** accessory if you can find on on eBay or in an actual camera store's junk bin.


----------

