Can we get a bit closer

Wide angle macro photography is my favourite phototechnique. Modern fisheye lenses have relatively good close-focus abilities; therefore they’re excellent tools for this kind of photography. Sigma 15mm fisheye is excellent regarding this and the sony fisheye converter (VCL-ECF1) on the 16mm macro is also quite good if you want to go close to your subject. However, going even closer would be nice sometimes. Since you can’t add close-up lenses to a fisheye lens, the only solution is extension tube. I’ve quickly tested a 10mm tube on my sony nex with the 16mm+ VCL-ECF1 combo, but the effect was too strong. However, I’ve seen recently an excellent photo from Nikola Rahmé, who is one of the best macro photographers. Check his photo here:

https://www.flickr.com/photos/eurythyrea/19565832992/in/dateposted/

He used a custom made 8 mm long extension tube with sigma fisheye. I really like the effect on his picture, so I kept experimenting with the idea. I’ve simply detached the lens from the camera and held simply in front of the camera to mimic the effect of an extension tube. Pushing it to the mount gives you 6-7mm distance and it worked. These photos were taken with the closest focus distance, when the lens attached correctly (stopped down and opened iris):

This one is taken by handholding the lens few mm away from the camera. The flower is relatively small (around 30 mm in diameter):

I've also tried it with a gooseberry (check my arm):

Some suggestions for this technique:

• · Focus manually the lens to infinity (set focus mode to manual) otherwise the subject will be just too close and it will practically touch the lens.
• · You can set the aperture before you detach the lens (when the camera is on) and the lens will keep the set values.
• · Lighting the subject will be necessary most of the case, which is quite challenging due to the close focus distance, but not impossible if you use optical fibres to direct the light from the main flash to the subject.
• · This technique, of course, requires a tripod and subjects stay still.

It’s most probably easier to do it with a samyang/rokinon manual fisheye lens, where you can easily alter focus and iris even when the lens is detached. I quickly tried with the sigma 15mm fisheye on an adapter and it worked also fine. Fine tuning of the focus was also possible. Sorry to photograph my orchids again. Some photos below with the sigma fisheye that was designed for full-frame cameras, so the nex-5, I used actually cropped the field of view.

Here the photo when the lens attached normally:

At the end, the best approach would be for this technique a sigma 15mm lens attached to a helicoids adapter and used on a full-frame camera (A7 series). Such helicoids adapters work as variable extension tubes, so the effect can be modified easily. For example on this quenoX adapter the distance rack out from 0 to 6 mm.
http://www.enjoyyourcamera.com/Objektivadapter/Adapter-an-Sony-NEX/Alpha-E-Mount/Ausfahrbarer-Helicoid-Objektivadapter-Canon-EOS-Sony-Alpha-NEX-E-Mount-wie-Zwischenring::7201.html

No need for awkward handholding, so I can imagine that the technique could be even used without a tripod with such set-up.