Reversing 50mm?

Macro guy wrote:

...............

However, most lenses for non-view cameras are not symmetrical. Therefore, whenever you reverse mount a lens, you get somthing called lens reversal extension and that affects your magnification. The reversal extension is dependent on the optical formula of the lens, so it will be different for every lens.

Interesting.

Hence the disparity between what BBbuilder467 was experiencing vs. what I was. Also between the two 50mm Nikkor lenses (1.2 vs. 1.8) on the Nikon spec sheet.

You have to account for that with cameras that have no through the lens metering systems, however, since all digital cameras have a built in meter, the reverse extenstion factor is irrelevant.

I guess what's relevant is the lens you choose, plus the camera you're using it on.

Since Nikon has such a steeped history in MF glass, that is so easily-mounted on virtually anything, most people choose to reverse-mount Nikkor AI/AI-S glass to their cameras, regardless of their preferred camera system.

At the end of the day, they can verify everything simply by viewing Nikon's own sheet, then taking a photograph of a mm ruler, in measuring "the amount of mm" framed by that optic.

In my original post on this thread, the Zoom Nikkor I suggested had the greatest versatility, whereas when using a prime, you're pretty much stuck at that focal length/magnification.

Macro guy wrote:

I prefer mounting the reversed lens on a bellows. I find that type of a setup gives me the greatest flexibility. I can change my magnification with a given lens (within that lens' focal length parameters) and I can focus without changing my magnification.

Here's what my setup looks like. It's not the greatest pic, I took it with my phone, but you get the gist.

Our setups are similar, except mine is more for the field than the studio. It'd be pretty difficult to hand-hold that set-up. I think a bellows is really only necessary for super-high magnification, again in the studio, which is all but impossible to get on live subjects, especially in the field.

I do much more field work than studio shots, and I only shoot live subjects, preferably in their natural environment. My studio set up is pretty complicated, if I find uncooperative subjects in nature that require studio placement. But it's such a hassle, that I never bother with it much anymore.

Here's my field setup, for live subjects, using reverse-macro:

Zoom Nikkor AI-S 28-85mm f/3.5-4.5 AI-S reverse-mounted on D500

The diffused flash is not shown.

The reversed-zoom lens is capable of going from .25 to 2.9x. Even when I used to shoot the MPE 65, I rarely went over 3x, so shooting @ 4-5x is of no real interest to me.

If I have an immobile subject, like a crab spider, I'll use the tripod + macro rails to develop stacks, but not the flash. I prefer natural light, wherever possible.

However, if I have a moving subject, like a jumping spider or other, then I just unsnap the camera from the tripod and deploy the camera + flash handheld, stopping down for DOF, rather than stacking.

These days, I've replaced reverse-lens macro with Laowa macro optics. Still, I enjoy reverse-macro photography for fun sometimes, but the Laowa glass is pretty good.

Very nice- looks high tech. I'm not there yet. I bet you get some great shots with this set up.

gardenersassistant wrote:

3D Gunner wrote:

gardenersassistant wrote:

What is puzzling me here is the "as long as", which presumably means the lens can't focus if it isn't at the proper distance from the sensor. However, if your options 1 and 2 put the lens at the right distance from the sensor so it can focus, how is it that the reverse to body option I used also allows the lens to focus, with it being at the wrong distance from the sensor? I used

3. m4/3 body + reverse ring + reverted lens

which puts the reverted lens closer to the sensor than your options 1 and 2.

It's about the minimum distance required between the lens and the sensor.
The adapter between different mounts provides the minimum distance needed (at least).
Using the bayonet-to-lens-thread adapter requires a few extra extension rings to get the minimum distance needed for imaging on the sensor.

I just mounted a Canon EF-S 18-55 reversed directly on to a reverse ring on a G80. Both have 58mm threads so no extension rings were needed to make the physical connection. It focused fine all the way through from 18 to 55mm. I then did the same with a Panasonic 14-140mm (the only other lens I have with a 58mm filter thread). It too focused fine without the need for any extension rings.

The m4/3 will focus with the lens reversed directly to the body, but a prime lens doesn't get the appropriate magnification. You need to use a prime to test. A 50mm prime should be 1:1 when reversed.

See what you get when you reverse a 50mm prime directly to the body. Even with the adapter, it still seems to need a few mm extension to be accurate. It's around 30mm from the body to the face of the lens.

BBbuilder467 wrote:

gardenersassistant wrote:

3D Gunner wrote:

gardenersassistant wrote:

What is puzzling me here is the "as long as", which presumably means the lens can't focus if it isn't at the proper distance from the sensor. However, if your options 1 and 2 put the lens at the right distance from the sensor so it can focus, how is it that the reverse to body option I used also allows the lens to focus, with it being at the wrong distance from the sensor? I used

3. m4/3 body + reverse ring + reverted lens

which puts the reverted lens closer to the sensor than your options 1 and 2.

It's about the minimum distance required between the lens and the sensor.
The adapter between different mounts provides the minimum distance needed (at least).
Using the bayonet-to-lens-thread adapter requires a few extra extension rings to get the minimum distance needed for imaging on the sensor.

I just mounted a Canon EF-S 18-55 reversed directly on to a reverse ring on a G80. Both have 58mm threads so no extension rings were needed to make the physical connection. It focused fine all the way through from 18 to 55mm. I then did the same with a Panasonic 14-140mm (the only other lens I have with a 58mm filter thread). It too focused fine without the need for any extension rings.

The m4/3 will focus with the lens reversed directly to the body, but a prime lens doesn't get the appropriate magnification. You need to use a prime to test. A 50mm prime should be 1:1 when reversed.

See what you get when you reverse a 50mm prime directly to the body. Even with the adapter, it still seems to need a few mm extension to be accurate. It's around 30mm from the body to the face of the lens.

For the setup that gives 1:1 the distance from the body to the face of the lens is around 55mm.

gardenersassistant wrote:

BBbuilder467 wrote:

gardenersassistant wrote:

3D Gunner wrote:

gardenersassistant wrote:

What is puzzling me here is the "as long as", which presumably means the lens can't focus if it isn't at the proper distance from the sensor. However, if your options 1 and 2 put the lens at the right distance from the sensor so it can focus, how is it that the reverse to body option I used also allows the lens to focus, with it being at the wrong distance from the sensor? I used

3. m4/3 body + reverse ring + reverted lens

which puts the reverted lens closer to the sensor than your options 1 and 2.

It's about the minimum distance required between the lens and the sensor.
The adapter between different mounts provides the minimum distance needed (at least).
Using the bayonet-to-lens-thread adapter requires a few extra extension rings to get the minimum distance needed for imaging on the sensor.

I just mounted a Canon EF-S 18-55 reversed directly on to a reverse ring on a G80. Both have 58mm threads so no extension rings were needed to make the physical connection. It focused fine all the way through from 18 to 55mm. I then did the same with a Panasonic 14-140mm (the only other lens I have with a 58mm filter thread). It too focused fine without the need for any extension rings.

The m4/3 will focus with the lens reversed directly to the body, but a prime lens doesn't get the appropriate magnification. You need to use a prime to test. A 50mm prime should be 1:1 when reversed.

See what you get when you reverse a 50mm prime directly to the body. Even with the adapter, it still seems to need a few mm extension to be accurate. It's around 30mm from the body to the face of the lens.

For the setup that gives 1:1 the distance from the body to the face of the lens is around 55mm.

That's what I've been trying to tell everybody. You don't get any magnification reversing the lens directly to the body. The PK adapter alone is 25mm.

BBbuilder467 wrote:

Just for curiosity, I'd like to reverse a Pentax 50mm SMC-M, all manual lens to my micro 4/3.

I can't remember if I need to reverse directly to the body or reverse to the adapter to get the 1:1 magnification.

Has anyone tried it? With extension tubes, I need to use the adapter to get accurate ratios, so I assume I need to reverse to the adapter. I'd need the reverse mount for Pentax K instead of m4/3?

Not sure if the discussion has clearly answered this, so please ignore this if it has.

You could use an M43 to PK adapter and then a PK reverse ring on the PK side. To get extra distance to the lens you could then use M43 extension tubes on the m43 side of the adapter or PK extension tubes on the PK side.

Alternatively you could use an M43 reverse ring without using the PK adapter. You would be limited to using M43 extension tubes to get extra distance to the lens.

I did some measurements with a reversed Minolta 35-70 this morning. I used an M43 reverse ring, with and without M43 extension tubes. And I used an M43 to EF adapter, with and without EF extension tubes and an EF teleconverter on the EF side of the adapter. It turns out that this sort of setup can give a good range of magnifications without having to adjust the setup by changing extension tubes etc.

Looks amazing! Thanks for sharing.