Friday, February 9, 2007

Macro Photography with 50 mm f/1.8...

I mentioned before (for Table Sugar) that a reversed lens on the front of another lens makes a macro (close-up) lens. The problem is that with all that glass in the way the pictures aren't that sharp and vignetting is pretty horrible.

You can also do decent macro work with single reversed lens on the front of your camera. The most common lens for this is a 50 mm prime because they are cheap and have good optical quality. The advantages are decent macro magnification (about 1:1), good sharpness, and good brightness because you only have a single lens with a pretty big aperture. The downside, unless you shell out a lot of money for an adapter, is you lose ability to control aperture. (Obviously, a dedicated macro lens will tend to be a bit sharper and much brighter, but cost a heck of a lot more than using a lens you already own)

Before I bought anything, I decided to try it out just holding a lens up (backwards) to the camera and seeing how well it worked.

I decided to go ahead and get set up for a reversed Canon 50 mm f/1.8 prime. This is one lens pretty much everyone has because it is so cheap yet so good for portraits on a digital body with a less-than full frame sensor. The set up includes the lens ($80), a $11 52 mm reversing ring (which screws into the front of the 50 mm lens and fits into the 350D body like a lens), and a $18 extension tube set (fits between body and lens (or reverser) for a total extension of up to 65 mm). I bought the reversing ring and extension tubes from the same seller on eBay.

The sensor on the Rebel XT (350D) is 22.2 mm wide, so to get a 1:1 macro we'd need a field of view of 22.2 mm. Using the extension tubes and reversing ring, I found the following:

  • Unreversed lens: 150 mm field of view (1:6.76)
  • Unreversed lens w/ full 65 mm extension tube: 15 mm FOV (1.47:1) but only a 3-4 cm working distance from the object.
  • Reversed lens, no tubes: 30 mm FOV (1:1.36), 10 cm working distance
  • Reversed lens, min tube (14 mm extension): 21 mm FOV (1.04:1), 8.5 cm working distance
  • Reversed lens, full tube (65 mm extension): 11 mm (2:1), 6.5 cm working distance
I highly recommend extension tubes with the reversed lens. The increase in working distance is very useful because the smaller range causes the camera to block most of the light.

Also, to set the aperture, put the business end of the 50 mm prime back on the camera, set the aperture in Av mode, push the depth of field preview (little button underneath the lens release button) and while holding it down, remove the lens. This causes the lens to have the aperture stuck even though it is off the camera. Obviously, this is not a recommended way to use the lens, but it works. Even better might be finding an old 50 mm prime at a flea market that has aperture options.

This set up tends to have a really small field of view (common for all macro work, actually). In particular, it is hard to get a decent field of view without stopping down the lens too much and getting a really dark viewfinder. But... putting the camera on a tripod helps a lot in terms of setting up shots and preventing camera shake. Just make sure you turn mirror lockup on and use a remote release to avoid vibrations.

When reversed, for whatever reason, the focus wheel on the lens does nothing. I haven't figured out why yet.

Also, reversing the lens can be pretty hard on the lens (which is why you want to use a cheapy like the 50 mm f/1.8). After all, you'll be inserting/removing the lens a lot (on both sides), the weight of the lens will be held by the end-cap, and you'll be putting a decent amount of force on the filter threads. But, if I break my 50 mm prime, I won't be too disappointed because they are so cheap.


Anonymous said...

I was looking for info on how to use an FD lens (reversed) on an EOS to copy slides and I found your post. Is the 50mm lens you used an FD lens?
I have an FD slide copier that I could attach to a 50mm 1.4 lens. I want to do 1:1 copies, but the ability to do a bit of cropping would be handy sometimes
I'm happy to by adaptors and extension tubes if they will do what i want. I just don't want too much trial and error


Sean said...

In this case, I was using the EOS/EF 50mm f/1.8. The downside of that lens is you have to set the aperture in a tricky way since it doesn't have an aperture control.

Currently, I use a Nikkor-H 50mm f/2.0 for reversing. It is very convenient.

I looked into the FD 50mm lenses, but the FD system has some quirks when it comes to adjusting the aperture on the fly (you need a special lens-cap/adapter thing). The Nikkor has a lever which you pull to open it up, release it to stop it back down again. Very convenient.

The post where I discuss the FD lens is here.

Anonymous said...

hello, I have got necessary things to attach my 50mm reversed on 350D body. now there is no connection between lens and the camera. So now am I supposed to first attach 50mm normally on av mode and while holding dof button, detach it and again attach it reversed? Will this work? And how safe is it to do such thing?

Sean said...

Yup, that's what you do. Holding the DOF button stops the aperture down, and if you remove the lens while stopped down it will stay stopped down. To put the lens back to normal (wide open) just reconnect it and turn the camera on (or reconnect it with the camera on). I recommend reopening the aperture when you are done shooting, just in case storage causes it to stick.

With the usual caveat that I'm not a camera technician so don't sue me, this move is totally safe. I've done it on my 350D probably 50 times with no problems. The only real problem with it is it is inconvenient to flip the lens every time you want to change the aperture (not to mention how dark the viewfinder is stopped down all the time). But it is an easy, cheap way to start out in macro.

To upgrade a little (without spending $250+ on a new macro lens) get a used Nikon lens (my review). It'll cost $20-$30 but it uses the 52mm reversing ring and gives manual aperture control (very convenient). I've made a lot of macro posts, many of them using that lens. IMO, the Nikkor 50mm yields sharper images than the Canon 50mm. At minimum, it's three times easier to use!

For a little more, ($70+) you can get an FD macro lens like the 100mm f/4. That'll give you focusing control and a lot more working distance but you'll also need an FD-EOS adapter. The 100mm f/4 is my current cheapy macro lens, and I just realized that I never reviewed it :( Honestly, I haven't worked with it that much, maybe I should dust it off soon.

Anonymous said...

thanks mate, for this information.