In my post on lens reversal technique for macro photography, I mentioned some challenges you face when you reverse a lens for macro photography. So, in this article, I shall explain how to overcome those challenges to take better photographs using this technique.
Read: Poor Man’s Macro — The lens reversal technique
Secrets of Macro Photography Using Reverse Lens
Choice of lens, magnification, and image quality
Using this technique, you can reverse any type of lens you want. So how does one select the type of lens for reverse mounting for macro photography?
The concept is very simple. Wide angle lenses (in normal mount) decreases the magnification of the subject. That means, the image appears on the sensor is small than the real size. And telephoto lenses in normal mount increases the magnification of the subject.
So the idea is, to achieve high magnification, you can reverse a lower focal length lenses. When the focal length of the reversed lens is small, the magnification is high. For example, when you reverse a 28mm lens, you get a 3X magnification. And, when you reverse a 50mm lens, the magnification is 1X or 1:1. So, if you reverse a lens with a focal length more than 50mm, the magnification will be less than 1:1.
If you are reversing a wide angle lens, say, an 18-55mm kit lens, you can adjust the magnification by changing the focal length. I.e. magnification at 18mm is higher than the magnification at 55mm. The drawback, of using a reversed 18-55mm kit lens, for macro photography is:-
- You don’t get sharp images.
- When the focal length is at wide angle ranges (below 28mm), vignetting occurs (dark areas around the corners)
I always prefer reversing a prime lens for macro photography. Why? Because there is not much optics present in prime lenses. Thus, they give sharp images. The only drawback is that you cannot change the magnification as you can do with a zoom lens. That is, if you wish to change the magnification, you need to have several prime lenses of different focal lengths.
So, the selection of the lens for macro photography depends on:
- The magnification you want to achieve
- Image quality
How to change the aperture? — The F00 issue
A lens in reverse mount does not have any electronic contact with the camera. So, you cannot change the aperture of the lens from the camera. Because of this, the camera displays the f-number as f00 (as shown in the picture) Then, how do you change the aperture? Well, it depends on the lens you are using:
Some lenses have an aperture ring to change the aperture size. For such lenses, you can use the on lens ring to change the aperture.
For those lenses which do not have an aperture ring, the f-number has to be set in advance before reverse mounting it. Here is how it is done in canon cameras:
- Mount the lens normally
- Set the desired f-number.
- Now press the Depth of field preview button (shown in the picture). This closes down the aperture to the f-number you have set. So, while depressing the DOF preview button, detach the lens from the camera.
- Reverse mount your lens.
How to control the depth of field?
When the magnification increases, the depth of field will become too shallow. i.e. the area of focus will be small. It results in blurry images. So, the selection of aperture depends on the magnification of the subject. Here’s how you should select the aperture for macro photography:
For the same f-number, the depth of field is inversely related to the magnification of the subject. Confused? Okay, let me make it clear to you: At f8, a 3:1 magnification would give a more shallow depth of field than the depth of field at 1:1 magnification OR At 1:1 magnification, the area of focus at f8 is larger than the area of focus at 3:1 magnification.
So the bottom line is, to get more area in focus, choose a larger f-number depending on the magnification. I usually go for f8 (or f9, depending on the available light) when I use reversed 50mm – 1:1 magnification. And for a 2:1 magnification, I prefer f11 to get more area in focus.
Since the lens loses its electronic contact with the camera in reverse mount, you will not be able to use autofocus function. Also, manual focus will not work because of the lens’ close proximity to the subject. A reverse mount lens has a fixed plane of focus. So the only solution is to physically move yourself, or the subject, into focus. So using a tripod is practically impossible.
You cannot trust your camera’s inbuilt light meter once you reverse the lens. So you have to do some trial and error to find a good exposure. Another important issue you experience is the loss of light. As I have mentioned before, you have to use a narrow aperture to control the depth of field. So, obviously, there will be some loss of light. The solution is to increase the ISO or decrease the shutter speed to let in more light. But this may result in noisy and blurry images respectively. Another solution is to use a flash. But, since, flash produces harsh light, you have to use a diffuser to create soft light. However, if the light is too soft, you cannot capture the details on the subject.
Putting it all together
An optimal setting is important for getting good results. The choice of aperture is crucial as it controls the depth of field and light coming into the camera. I.e. if you choose a very small aperture to control depth of field (large f-number), it cuts down the light. And even if you use a flash along with it, you would get a low key image. So select the f-number wisely – make sure you get enough natural light and a proper depth of field.
A reality check
To be frank, macro photography using a reverse mounted lens is not the best technique. It has a lot of limitations – the autofocus will not work, which makes it difficult to photograph moving subjects; loss of natural light as you have to use narrow apertures, and if you are taking macro photographs of insects, getting close to them might scare them away. So you need a lot of patience and practice to get the hang of using this technique. But I can assure you that the end results are rewarding — it matches images taken from an expensive macro lens. Anyway, it’s a very cheap technique for macro photography. So why not give it a shot.
I have told you my secrets. So, Are you ready to try this technique out? Share your results in our Flickr group: Shutterstoppers Flickr group
I have published a new article on how to use reverse lens technique for high magnification macro photography.