This extreme-macro technique for SLRs changed my world.

This extreme-macro technique for SLRs changed my world.
Although I'm not a fan of the blur, I can get a pretty tight DoF using a +4, +2, and +1 magnifying filters.

p.s. I had no idea poppyseeds looked like that.

Although I'm not a fan of the blur, I can get a using a +4, +2, and +1 magnifying filters.

p.s. I had no idea poppyseeds looked like that.

this guy

Exactly! Need a lot of light with two lenses. I did what did. Still need a lot of light, but with flash on and a reflector it's more than enough.

edit: typo's. Just woke up. Hang over. Not good.

The additional lens is turning the combined lens system into a lens with much shorter focal distance. (It's easier to understand, IMHO, if you think in terms of diopters rather than focal lengths, but the idea is the same: adding converging lenses together makes them act like a stronger-converging lens. Same as if you stack regular magnifying glasses and get a stronger magnifying glass.)

And now you're going to ask: So why is the magnification different depending on which lens is in front?

Good question. :) The reason is that the two lenses combined act like they are a single lens, but where is this virtual lens they are acting like?? Depending on which way you mount the lenses (long lens first or short lens first), this changes the location of this virtual lens (relative to the sensor).

And that is what magnification is all about: How far your lens is from your sensor. In both cases, this is the underlying issue.

To be more specific, what you want to pay attention to is the distance from your sensor to your virtual lens measured in focal lengths.

This is how I got such high magnification: I used an extremely short lens (14mm), so I only had to move the lens out 11x14mm = 15.4cm from the sensor. (When mounted on the camera, the virtual lens is, of course, 14mm away from the sensor, so I moved it 14cm further than that.)

Did any of that make sense? :)

It's the close up! Ok, I know they all say they are "close ups", but IT'S THE CLOSE UP!

Edit: I should submit a new picture. I was just screwing around that day. My sensor was all dirty, and I have a much better camera and much sharper lens now.

Not by doing the math based on the optics equations. :) I always get something wrong.

Just take a picture of a ruler with millimeter markings. Let's say your image was exactly 4mm across. Then figure out what percentage of your sensor 1mm is. Mine camera is full-frame, so 36mm across. Divide sensor by image, so 36/4 = 9x magnification (which is pretty insane).

Usually, however, your image isn't exactly 4mm. In fact, even if it was, it would be really hard to get the camera lined up exactly. So I usually just try to figure out how many pixels of the image 1mm is, then divide the total number of pixels by that.

So my camera (5Dmk2 -- I totally love it) is 5616px across. If I took a picture of a ruler and found that 1mm was about 1400px across, then 5616/1400 = about 4mm.

Then you want sensor-width-in-mm over that number. So in my case, as I always use the same camera, the sensor size in mm and in px is constant. So the equation becomes:

M x 36.0 / 5616

where M is the measured pixel size of 1mm -- 1400px in the above example.

So you just need to change the 36.0 and 5616 to be whatever your camera specs are.

Here's a picture of a penny I took after watching this video.  

I used my D80's 18-135mm kit lens (zoomed all the way to 135) with my 50mm 1.8 on the other end. I tried experimenting with different apertures on the zoom to try to affect the depth of field but I don't think it makes any difference at this level; it only seemed to influence vignetting.  

I bumped up the contrast in Lightroom on it.  

EDIT: Oh, I also had my SB-600 firing on it at 1/128th power just a couple inches away.

Here's a picture of a I took after watching this video.

I used my D80's 18-135mm kit lens (zoomed all the way to 135) with my 50mm 1.8 on the other end. I tried experimenting with different apertures on the zoom to try to affect the depth of field but I don't think it makes any difference at this level; it only seemed to influence vignetting.

I bumped up the contrast in Lightroom on it.

EDIT: Oh, I also had my SB-600 firing on it at 1/128th power just a couple inches away.

Oh wow, that kicks ass; looks like a false-colour image of viruses or some other microbes on the hunt. Nice capture!

How does it feel being "the other Chris Pine"? I'm mostly just bitter because I used to be at the top of a google search. (He couldn't have gone by Christopher??) I was lead programmer on Civilization 3. I wrote a book! These things should be enough, dammit. And they were enough. For a few, brief years, they were...

At least I still show up on the front page of a google search. That's something. I get some of his fan mail. I've heard from one of his fan clubs that I actually make their lives a bit more complicated, so at least there's that to be proud of: I slightly, though consistently, annoy a few teenage chinese girls.

Anyway. Your other question needs an answer.

The important equation for a converging lens (which all camera lenses are) is right at the top of that page:

1/distSensor + 1/distObject = 1/focalLength

Assuming a fixed focal length, this means that when distance-to-the-sensor increases, then distanct-to-the-object (or to the focal point, if you prefer) decreases. It's not exactly an inverse relation, but certainly when one increases, the other decreases.

And "distance from the lens to the sensor", of course, refers to the virtual lens. In a single-camera-lens system, this is easy to find: It's exactly one focal length from the sensor when the lens is focused at infinity. (Your camera most likely has a sensor mark on the top; check your manual.)

In the case of my 14mm lens, this meant that the virtual lens was located outside of the frickin lens! Behind it, inside the camera. (I later found that it's called a retrofocal lens, and is the opposite of a telephoto lens, where the virtual lens is located in front of the physical lens; in both cases the construction of the lens is actually kind of similar, just reversed. Which is pretty cool. :)

Anyway, with my 14mm, this also meant that moving it even a few mm was enough to move the focal point inside the physical lens, making focusing on anything impossible. That's why reversing the lens works so well: that can never happen when you reverse a lens. (Well, except for a telephoto lens, but by the same reasoning, you will never need to reverse one of those.)

Edit: I wouldn't need to edit if they just had a preview button. Come on, Reddit, it's not 1999 anymore.

Not really. I got 11x magnification with a reversed 14mm lens. (That's enough to see pollen and plant cells!)

Using two lenses is a different technique, but it's not a stronger one. I personally prefer using a single lens because the vignetting gets insane when you double up like that (unless I was doing something wrong, but I see others getting the same results).

All you have to do to get more magnification is to move the lens farther away from the sensor/film.