FD to M43 focal reducer problem, also which FD lens do you suggest ?

Started 8 months ago | Questions thread
adygadam
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Re: FD to M43 focal reducer problem, also which FD lens do you suggest ?
In reply to Eric Nepean, 8 months ago

Eric Nepean wrote:

adygadam wrote:

Eric Nepean wrote:

I have the Metabones focal reducer, have been a user of FD lenses since I got my Ftb in the 1970s.

adygadam wrote:

Hello All,

I own a Panasonic GH3 and 4 days ago took the plunge finally after a long debate on speedboosters/focal reducers and ordered a focal reducer FD to M43 from here:

Camdiox Focal Reducer FD to M43

I also ordered an adapter: Canon FD to M43 adapter

A got myself a Canon FD 50mm F1:1.4 S.S.C. lens which is amazing ! No dust specs or fungus and in excellent condition.

The adapter worked like a charm, I was able to change the aperture from F16 down to F1.4 and I believe the FF equivalent focal length would be 100mm (50mm x 2), bokeh was amazing a this makes this lens an excellent short distance portrait lens.

The problem was with the focal reducer, I was only able to stop down to F4.8, after that the aperture was the same to F16. On the contrary the adapter allowed me to stop down to F16.

I have noticed that when I mount the lens to the adapter the chrome ring will turn around 2 inches until it tightens, whereas with the focal reducer it will turn around 4/8 of an inch before it tightens.

Is this normal ? Is the focal reducer faulty ?

The Chrome mounting ring turns between 1 inch and 1 1/2 inches on my various bits of FD gear - the 1/2 inch you mention sounds a little short. I note that with plastic end caps, the mounting ring only turns about 1/2 inch. IMO it quite possible there is an interlock in the chrome mounting ring.

The Chrome ring actually turns on a screw thread on the lens barrel, so how far it turns depends on the thickness of the mating part on the lens mount on your Focal reducer. You could return it and argue that the mount is out of tolerance.

This is exactly what I thought, the thickness of the lens mount on the adapter is about 0.85mm and the one on the focal reducer is around 1.15mm, so I guess this is preventing the lens from rotating a further 1/2 inch to make a perfect fit ?

That's what I think - I haven't seen you adapter, but my understanding is based on what I saw when removed the chrome ring from one of my Canon Macro extension tubes for another project.

With FD lenses, there is a work around to your problem - in fact its my preferred way of using an FD lens on an M43 camera. On the back of the FD lenses, there are two protruding levers - one is longer than the other. With the rear of the lens facing you, slide the longer lever counterclockwise as far as it will go - towards the end of travel there is a little resistance and then it will snap into place. Now the lens aperture is always closed to the setting on the aperture ring.

On some FD lenses (newer perhaps?), the mechanism is slighly different - there is a very small lever flush to the metal surface, this locks the protruding lever at the end of its travel.

Apart from being unable to stop down any lower than F4.8 using the focal reducer, the focus is working alright and the FF equivalent focal length I believe is now 72mm (50mm x 0.72 x 2) with an amazing F1.0!.

I have the following native M43 lens:

Olympus Zuiko 12mm F1:2.0

Panasonic Lumix G X 12-35mm F1:2.8

Also I have the following FD lens:

Canon FD 50mm F1:1.4 S.S.C. (with adapter: 100mm F1.4, with focal reducer: 72mm F1.0)

Tokina ATX SD 80-200mm F1:2.8 (bought recently)(with adapter: 160-400mm F2.8, with focal reducer: 115-288mm F2 !)

I am thinking about buying this one:

Canon FD 35mm F1:2.0 S.S.C. (with adapter: 70mm F2.0, with focal reducer: 50mm F1.4)

What do you suggest for a close alternative to what you can get from a Voigtlander 25mm (FF=50mm) F0.95, I guess this Canon FD35mm with a focal reducer will be the best you can get on FD ?

Many thanks.

As you have done, I have found that the FD50mm F1.4 lens with focal reducer makes a 35mm F1.0 lens (FF equivalent FOV 72mm DOF F2.0) this quite handy. With the Metabones, the image is quite sharp.

I also have the FD135mmF2.5 which with the speedbooster becomes 96mm F 1.8 (FF Equivalent FOV 190mm DOF F3.5) Unfortunately the lens itself is not that sharp until you stop it down a few stops.

Another interesting combination would be the FD100mm F2.0, which would become 71mm F 1.4

However I have looked and I don't see any useful combos with the original lens focal length below 50mm; the native M43 lenses are better.

The best below 50mm at reasonable price would be the FD 24mm F2.0 which becomes a 17mm F1.4 lens which isn't that interesting because Olympus has a 17mm F1.8 lens, which is automatic and not to expensive, and the extra one third stop isn't that significant at 17mm.

Even if you had a bigger budget to buy the FD24mm F1.4, about $1000 used, with .71x Focal Reducer would be come 17mm F1.0 which would be interesting, but for that price you may as well buy the 17.5mm Voigtlander F0.95 in native M43 mount and get a better lens.

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Eric

Thank you for your suggestions, looks like the only useful lenses would be telephoto ones as they will be extending the reach of the lens, however I am not planning on doing any very long shoots I guess the Tokina 80-200 will be more than enough for any interesting far shoots.

I have noticed that according to what you had said a 2 full stops are lost when converting to FF even though it was already gained with the speedbooster/focal reducer ?

CheersDamian

I believe it works this way: (example) You start with a FD 50mm F1.4 lens. The .71x focal reducer adds a lens element, which shortens the focal length to 35mm. But the F ratio is the radio of aperture diameter to focal length, so by shortening the focal length, the F ratio changes.

For the 50mm lens alone the effective aperture was 50/1.4=35mm With the focal reducer, the maximum effective aperture has not changed, but the focal length is also 35mm. So F1.0.

Now, lots of folks wish to compare M43 lenses against lenses used in the historical 35mm film standard. Sometimes because they are very familiar with that reference, but doing this also provides a common reference for comparing lenses used on various sensors.

The diagonal of the M43 sensor is about half that of the 35mm film - the crop factor is two.

So the Field of View of the 35mm lens will be the same as that of a 70mm lens used for 35mm film.

At F1.0 the depth of field is 3 ft at 20ft, which is the same as a 70mm lens at F2.0 (check it with http://www.dofmaster.com/dofjs.html ). This doesn't change you exposure - your shutter speed is still determined by F1.0, your ISO and the illumination.

This is very interesting indeed, looks like that even a tracking for a slow moving subject with Voigtlander 25mm F0.95 wide open is a pain at a distance of 8ft giving you clearance 1 ft.

Thanks for the link.

This isn't necessarily a bad tradeoff ... if you had a 70mm F1.0 lens on 35mm film, the DOF would be 1.5 ft at 20ft (a little tight), at 10ft your DOF would be just over 4 inches (a lot tight) ... I'd rather have F1.0 and the wider DOF.

I'm finding that even with the FD 50mm 1.4 half a stop down from wide open (for increased sharpness) + Metabones, the DOF is sometimes uncomfortable narrow.

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Eric

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Cheers
Damian

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