Full frame adapter (left), crop adapter (right)
This adapter allows you to use a cheap 4x microscope objective on a wide range of DSLR and Mirrorless cameras to take "ultra-macro" photography!
The adapter has been designed for hand-held shooting, using a flash for lighting to illuminate the subject and eliminate motion blur.
The long slimline design allows you to get much closer to your subjects without your rig colliding with leaves and pushing your subject out of the way.
Ordering
Which cameras are compatible?
There are two kinds of adapters available, a full-frame and a crop design. These are the supported cameras:
- Canon EF-S / EF (crop, full-frame)
- Canon RF (crop, full-frame)
- Leica L (crop, full-frame) (also used by some Panasonic and Sigma cameras)
- Nikon F (crop, full-frame)
- Nikon Z (crop, full-frame)
- Pentax M42 (crop, full-frame)
- Sony A (crop, full-frame)
- Sony E / FE (crop, full-frame)
- Fujifilm X (crop only)
- Micro Four-thirds (crop only)
The crop-camera version, for cameras with crop sensors (or for full-frame cameras which have been switched to crop mode) has a segment of tube you can remove to shorten the tube.
For objectives which cast an image circle big enough to fill a full-frame sensor, removing this middle tube allows you to reduce the magnification and widen the field of view to match that of a Full-Frame camera,
The full-frame version is a single-piece, without a removable tube segment.
Which objective to choose?
The 4x microscope objective I recommend to use with the adapter is this one from Reakway:
https://www.aliexpress.com/item/32360730919.html
This objective has excellent image quality across the whole full-frame sensor, which is rare (most objectives only fill an APS-C sensor). Note that there are some other objectives on the market which look similar externally, but are very different internally and with different performance, so I don't recommend buying from other listings.
My adapter is compatible with any RMS-threaded finite objective (i.e. marked with "160" or "150" rather than an infinity symbol).
Higher-magnification objectives like 10x are best used in the studio on a rail rather than hand-held due to their incredibly slim depth of field! But some may find this possible if their subject is on solid ground, and they can brace themselves as well.
Objectives of 20x or higher will be essentially impossible to use freehand, in part due to sub-millimetre working distances that will cause you to smoosh your subject!
The 4x objective I recommend can have its casing removed to extend the working distance significantly. It simply unscrews from the objective, but take care when handling it afterwards because the threads underneath are very sharp (I used a kitchen rubber glove when I needed to grip it for installation into the adapter afterwards):
Removal of casing for 4x objective
What results should I expect?
4x magnification on a full-frame sensor gives you a field-of-view of approximately 9×6mm, so you need to find some very small subjects! I prefer this, because I find that when I shoot with regular 1x macro lenses my subject ends up with a lot of wasted space around it that I have to crop off. But note that for larger insects like bumblebees, this will mean that you won't be able to take a full-body shot, you'll be taking a "head and shoulders" portrait instead!
At 4x magnification the depth of field is very thin, and there isn't any way to further close down the aperture to increase this.
So if you want to extend your depth of field, you need to shoot many shots at slightly different focus depths, and align and merge these together in a program like Photoshop.
This also gives you the opportunity to extend the angle of view of your image by shooting a "macro-panorama" - reframe your subject to add extra images around the periphery to give you more composition options when cropping your final shot. The same Photoshop stacking tools can handle these as well.
This comparison shows the difference between taking a just single frame (left), and the extended depth of field that I gained by stacking 8 individual frames (taken hand-held) using Photoshop:
Focus stacking comparison - Coffee bean at 4x
Not all subjects will require stacking. If you align your plane of focus just right you can get the important parts in focus with a single frame. Here are some examples:
Single-frame images at 4x
Hand-held focus stacks assembled in Photoshop
Guide to shooting with the adapter
Check out macro photographer Micael Widell's introduction to the adapter, so you can see what it is like to use in the field:
Because of the high magnification, the effective aperture of the objective is fixed at an aperture smaller than f/21, so diffused flash lighting is essential to provide enough light for your subject, and to freeze camera shake and subject motion.
Because of this effective aperture, if you are shooting on a traditional DSLR you will find that the viewfinder is very dim, and it is best to shoot in bright outdoor conditions so that you can see what you're doing.
Mirrorless camera users won't need to worry about this, because the camera can brighten up the viewfinder image for you (on Sony cameras you will need to select "Setting Effect: Off" so that the image is brightened up for you).
Take many photos of your subject, because even the photos where you missed your intended focus slightly can be stacked together to increase your depth of field using Photoshop.
When you become more proficient with shooting you will be able to deliberately create focus stacks by changing your depth slightly between shots (by moving the camera forwards or backwards).
I usually shoot with the camera in manual mode at ISO 100 (since my flash has plenty of power) and 1/160th of a second (which is the fastest shutter speed my camera supports when using flash). This renders daylight almost black, so the flash is the main contributor of light. I use manual mode on my flash too, and set the power to make the brightness of the image correct, which is about 1/8th power with my flash. Using manual mode on the flash ensures multiple images in focus stacks won't have much variation in exposure.
With these settings, the flash overpowers daylight and renders any distant background completely black, but this is usually fine for me at 4x magnification, since the background tends to be the same leaf my subject is standing on, so the final image doesn't have much distant black background in it!
It is possible to shoot a more balanced exposure, where the shutter speed is dropped to 1/40th, and the ISO bumped up to 800, to bring more daylight back into the image. But now you need to contend with camera shake if your subject has much natural light falling on it.
DIY
If you have your own 3D-printer you can print this adapter yourself, I've posted the design to Printables here.
Detail of Sony E/FE mount on full-frame adapter