Reverse prime macro lens

[Dmitri]

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]

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]

ok, just making sure. Thanks Derrel

 

[Dmitri]

Thats some DOF lol

 

[Overread]

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]

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

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]

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]

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]

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]

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]

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]

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]

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

 

[Dmitri]

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]

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.