Micro Four Thirds Focal Reducer Shootout

Started Feb 20, 2014 | Discussions
OP brian Senior Member • Posts: 1,176
Re: Micro Four Thirds Focal Reducer Shootout
1

Hemiyoda wrote:

Thanks for the test Brian! Best one I have found so far of these.

Have you had the possibility to test the Kipon Baveyes or the Zhongyi Mitakon Lens Turbo II ? How do these newcomers stack up to your excellent optical design?

Best regards,

Erik Berg

Hi Erik:

AFAIK, neither of those focal reducers are available in m43 mount versions.  At some point I'll get around to doing a DX-format shootout.

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Brian Caldwell

Jay Turberville Forum Pro • Posts: 12,917
Re: Micro Four Thirds Focal Reducer Shootout
1) Rear focal reducers increase lens speed, while front attachments do not.

2) Good rear focal reducers increase MTF, while front attachments invariably do not.

3) Rear focal reducers are extremely compact, and in fact they reduce the length of the system, while front attachments are very bulky and make the system much bigger.

4) Good rear focal reducers can be used with almost any SLR lens, while front attachments are restricted to a narrow range of lenses.

5) Good rear focal reducers don't impact the focusing performance of the main lens, while front attachments can introduce significant aberrations as focus is changed.

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Brian Caldwell

I would add that when front mounted to filter threads rather than a made for the purpose tube adapter, front (afocal) focal reducers can also add mechanical stress to zoom lenses that telescope in and out when zoomed and can add strain on the focus system for AF lenses that do not have internal focusing.  This may or may not be a big deal depending on lens construction and focal reducer in question.  But if the front focal reducer was not made for the purpose by the camera/lens maker, its a reasonable area of concern.  I happily abuse my 14-42 MSC II by mounting a Nikon focal reducer to it.  But if/when I kill that inexpensive lens with this abuse, I'll know who to blame.  Me.

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Jay Turberville
www.jayandwanda.com

Jay Turberville Forum Pro • Posts: 12,917
Re: Micro Four Thirds Focal Reducer Shootout

So the "exit pupil" is the iris/diaphragm which is somewhere between the glass elements depending on lens design?

The exit pupil is the image of the aperture stop as seen from the image (sensor or film) side of the lens.

That's kinda cryptic - right?  Here's what it means.  If you look at the back of a lens, the exit pupil is the circle (or hexagon etc. if stopped down) of light that you see projecting through.  Depending on the design of the lens, the location of that "circle" can be very different from the physical location of the lens iris.  So the exit pupil location isn't defined by the location of the iris.  It is defined by where the iris appears to be.

Bonus related concept 1:  The image of the aperture stop when viewed from the subject (front) side of the lens is logically called the entrance pupil. Its location can also be quite different than the location of the actual iris.

Bonus related concept 2: The exit pupil of constant aperture (constant aperture by optical design, not by electronic control of the iris) zoom lenses does not move when the lens is zoomed.  It will move for zoom lenses that change f-number when zoomed.  If you think of the exit pupil as projecting the image onto the sensor, this begins to makes perfect sense.

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Jay Turberville
www.jayandwanda.com

MichailK Junior Member • Posts: 31
Re: Micro Four Thirds Focal Reducer Shootout

This thread has been hugely informative along the links posted to other threads of very basic information! Many many thanx! It is funny how things may not be what you expect from a great lens of the past if you take account the sensor glass stack and the adaptor's optical qualities into play. It seems like a trial and error bet depending on the combination of sensor-lens-adaptor. What's fun is that  a great lady portrait photo may be so exactly because of degraded performance...

Jay Turberville wrote:

Bonus related concept 2: The exit pupil of constant aperture (constant aperture by optical design, not by electronic control of the iris) zoom lenses does not move when the lens is zoomed. It will move for zoom lenses that change f-number when zoomed. If you think of the exit pupil as projecting the image onto the sensor, this begins to makes perfect sense.

Interesting - my thick head tries to fully understand the implications besides the hot spotting problem. Is the image circle width related to the exit pupil distance? Does it change as this distance changes? (Among the lenses friends lent to me to use on my E-PL5 there is a seemingly rare Nikon zoom 25-50mm constant 1:4 Ai-S and a "common" Nikon 28-85mm 1:3,5-4,5 AF. I suppose that I could see for myself of the image circle projection on a piece of paper or so?) Could a too wide image circle produce a reflection haze of not fully absorbed light by the adaptor barrel walls that degrades shadows on high contrast bright daylight scenes?

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Jay Turberville Forum Pro • Posts: 12,917
Re: Micro Four Thirds Focal Reducer Shootout

Interesting - my thick head tries to fully understand the implications besides the hot spotting problem. Is the image circle width related to the exit pupil distance? Does it change as this distance changes? (Among the lenses friends lent to me to use on my E-PL5 there is a seemingly rare Nikon zoom 25-50mm constant 1:4 Ai-S and a "common" Nikon 28-85mm 1:3,5-4,5 AF. I suppose that I could see for myself of the image circle projection on a piece of paper or so?) Could a too wide image circle produce a reflection haze of not fully absorbed light by the adaptor barrel walls that degrades shadows on high contrast bright daylight scenes?

The exit pupil is not the image circle that would be projected onto paper. It is the circle you would see when you look directly through the back of the lens. Take the lens caps off of the constant aperture lens and look through the back while you zoom.  The opening you are looking through will not change size or location.  Now do the same with the variable aperture lens.  The opening on that lens will change size, location or both.

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Jay Turberville
www.jayandwanda.com

OP brian Senior Member • Posts: 1,176
Re: Micro Four Thirds Focal Reducer Shootout
2

Jay Turberville wrote:

Interesting - my thick head tries to fully understand the implications besides the hot spotting problem. Is the image circle width related to the exit pupil distance? Does it change as this distance changes? (Among the lenses friends lent to me to use on my E-PL5 there is a seemingly rare Nikon zoom 25-50mm constant 1:4 Ai-S and a "common" Nikon 28-85mm 1:3,5-4,5 AF. I suppose that I could see for myself of the image circle projection on a piece of paper or so?) Could a too wide image circle produce a reflection haze of not fully absorbed light by the adaptor barrel walls that degrades shadows on high contrast bright daylight scenes?

The exit pupil is not the image circle that would be projected onto paper. It is the circle you would see when you look directly through the back of the lens. Take the lens caps off of the constant aperture lens and look through the back while you zoom. The opening you are looking through will not change size or location. Now do the same with the variable aperture lens. The opening on that lens will change size, location or both.

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Jay Turberville
www.jayandwanda.com

Just a note:  A constant aperture zoom doesn't necessarily have a fixed exit pupil.  For example, the Sigma 18-35 f/1.8 has a constant aperture, but its exit pupil moves all over the place.  This is in fact why I chose this lens to study hotspotting - because I could vary the exit pupil at will and show significantly different effects.  Often in zooms like this the iris is cammed in order to maintain a constant f/#.  Fixed aperture zooms of the P-N-(P or N)-P type with a fixed rear group containing the iris will behave like you describe.

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Brian Caldwell

Jay Turberville Forum Pro • Posts: 12,917
Re: Micro Four Thirds Focal Reducer Shootout

brian wrote:

Jay Turberville wrote:

Interesting - my thick head tries to fully understand the implications besides the hot spotting problem. Is the image circle width related to the exit pupil distance? Does it change as this distance changes? (Among the lenses friends lent to me to use on my E-PL5 there is a seemingly rare Nikon zoom 25-50mm constant 1:4 Ai-S and a "common" Nikon 28-85mm 1:3,5-4,5 AF. I suppose that I could see for myself of the image circle projection on a piece of paper or so?) Could a too wide image circle produce a reflection haze of not fully absorbed light by the adaptor barrel walls that degrades shadows on high contrast bright daylight scenes?

The exit pupil is not the image circle that would be projected onto paper. It is the circle you would see when you look directly through the back of the lens. Take the lens caps off of the constant aperture lens and look through the back while you zoom. The opening you are looking through will not change size or location. Now do the same with the variable aperture lens. The opening on that lens will change size, location or both.

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Jay Turberville
www.jayandwanda.com

Just a note: A constant aperture zoom doesn't necessarily have a fixed exit pupil. For example, the Sigma 18-35 f/1.8 has a constant aperture, but its exit pupil moves all over the place. This is in fact why I chose this lens to study hotspotting - because I could vary the exit pupil at will and show significantly different effects. Often in zooms like this the iris is cammed in order to maintain a constant f/#. Fixed aperture zooms of the P-N-(P or N)-P type with a fixed rear group containing the iris will behave like you describe.

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Brian Caldwell

I was aware that some lenses were constant aperture via electronic control of the aperture and accounted for that in my initial comment about constant aperture lenses.  I guess it makes sense that you can do the same thing with a mechanical cam and that somebody would have done so.  I should have been more general in how I described the exception.

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Jay Turberville
www.jayandwanda.com

pmus2017 New Member • Posts: 1
Re: Shootout Part 2: Hotspotting

Hi Brian. Thanks very much for your article showing the hotspot issue. I have just bought the Speedbooster ULTRA for use with the Panasonic GH5 and my Sigma EF mount lenses and am getting the central bluish haze very badly on my Sigma 17-50mm f2.8 EX lens. I thought it was a fault but your article is the only thing I can find online & explains the issue. I understand that my lens has a much larger exit pupil distance (140.7mm to 187.4mm) which would explain why it is even worse than the 18-35mm lens you examined. I need to find a suitable alternative lens for my zoom but am finding it hard to get the exit pupil data from Canon ( they have a 17-55 f2.8 IS lens as well ). Do you have access to that data? I am hoping that there is another similar zoom available that avoids the issue, otherwise I may not be able to use the Speedbooster after all.

OP brian Senior Member • Posts: 1,176
Re: Shootout Part 2: Hotspotting
1

pmus2017 wrote:

Hi Brian. Thanks very much for your article showing the hotspot issue. I have just bought the Speedbooster ULTRA for use with the Panasonic GH5 and my Sigma EF mount lenses and am getting the central bluish haze very badly on my Sigma 17-50mm f2.8 EX lens. I thought it was a fault but your article is the only thing I can find online & explains the issue. I understand that my lens has a much larger exit pupil distance (140.7mm to 187.4mm) which would explain why it is even worse than the 18-35mm lens you examined. I need to find a suitable alternative lens for my zoom but am finding it hard to get the exit pupil data from Canon ( they have a 17-55 f2.8 IS lens as well ). Do you have access to that data? I am hoping that there is another similar zoom available that avoids the issue, otherwise I may not be able to use the Speedbooster after all.

Hi:

I have a sample of the Canon 17-55mm lens, but have not measured its exit pupil distance(s).  Bear with me because I'm currently a little busy, but will try to do the measurements relatively soon and will put the results on this thread.

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Brian Caldwell

SiFu
SiFu Veteran Member • Posts: 5,295
Re: Shootout Part 2: Hotspotting

Hello!

Please allow me a dumb question - what exactely is exit pupil distance? Distance from the aperture blades or rear element or ? to the sensor or? Or something different alltogether? Any pointers are highly appreciated!

Thanks and best,

Alex

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carpe diem, quam minimum credula postero

OP brian Senior Member • Posts: 1,176
Re: Shootout Part 2: Hotspotting
1

SiFu wrote:

Hello!

Please allow me a dumb question - what exactely is exit pupil distance? Distance from the aperture blades or rear element or ? to the sensor or? Or something different alltogether? Any pointers are highly appreciated!

Thanks and best,

Alex

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carpe diem, quam minimum credula postero

The exit pupil is the image of the aperture stop as seen from the rear of the lens.  The exit pupil distance is the distance from the exit pupil to the image plane.  To measure the exit pupil distance you first locate the exit pupil by stopping down all the way and focusing on the iris blades with an optical bench microscope looking into the rear of the lens.  Note that the working distance of the microscope objective has to be large enough to prevent crashing into the rear surface of the lens.  Then you open up the iris and move the microscope back to focus on the image plane (collimator required).  The distance you move the microscope is the exit pupil distance.

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Brian Caldwell

SiFu
SiFu Veteran Member • Posts: 5,295
Re: Shootout Part 2: Hotspotting

Hello Brian!

Thank you for your answer - unfortunately I am a bit language handicapped and not sure I understood correctly; in other words, are you measuring the distance from the iris blades of the lens to the image sensor in the camera as it would be with the lens mounted on the camera?

Best,

Alex

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carpe diem, quam minimum credula postero

OP brian Senior Member • Posts: 1,176
Re: Shootout Part 2: Hotspotting
1

SiFu wrote:

Hello Brian!

Thank you for your answer - unfortunately I am a bit language handicapped and not sure I understood correctly; in other words, are you measuring the distance from the iris blades of the lens to the image sensor in the camera as it would be with the lens mounted on the camera?

Best,

Alex

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carpe diem, quam minimum credula postero

Not quite.  You're measuring the distance between the *image* of the iris blades (as viewed from the rear of the lens) and the image plane.

When you look through the back of the lens at the iris blades you aren't looking directly at the blades, unless there is no glass after the stop - which can happen with some telephoto lenses etc..  The powered lens elements in the back of the lens change the apparent location and size of the iris diaphragm.  This is why what you are seeing is an image of the iris, not the iris itself.

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Brian Caldwell

MichailK Junior Member • Posts: 31
Re: Micro Four Thirds Focal Reducer Shootout

...just a post for any low production amateurs like me arriving at this thread as they look after the [FocalReducer+OldLens] interesting solution for shooting stills:

My amateurish opinion in short:

1. If you really need a Focal Reducer adapter, get the proper one and be done with it (get the Metabones) and stop mumbling about the price.

2. If you are not sure you really need or fancy such a device, get the much cheaper and 2nd best Zhongyi Lens Turbo, use it for some time and then decide whether to ditch the Focal Reducer idea altogether or to get the proper one (--> Metabones) and be done with "what focal reducer?" so you can concentrate on what lenses work best on it instead of scratching your head when results are found lacking for whatever reason (so do get the focal reducer quality out of the equation by getting the best).

Now, to elaborate more:

I never got any "proper" Metabones Speed Booster since back then I could barely afford a "Zhongyi Lens Turbo II Focal Reducer" for my MFT camera which I used for a few months last year coupled to three Nikon AiS lenses before selling it to fund a native MFT prime lens later on. Most use was with a prime 50mm/1.4 which gave me a nice calculated combo of 36mm/1.0.

What I found out is that the old lenses have their nice "feel" and "manual" fun but lack the sharpness and contrast sparkle that native MFT lenses provide (along modern commodities like autofocus). So for my hands it proved too easy to miss critical focus when using wide apertures and that made me use the Lens Turbo combo less and less over time for whatever intrigues me to take a shot of - I just got too soft results most of the time.

As far as this particular 36/1.0 combo goes, I did some homegrown comparative experiments and found out that the extravagant wide open spherical aberration(?) of the 50/1.4 Ais lens makes it usable for my kind of hobby photography only at narrower aperture than (Fcombo:2.0) and even then the lens turbo adapter robbed some of the already not great sharpness off the 50mm/1.4 lens. That is, this respectable FF 50mm lens at wider aperture than F4.0 on a plain adapter was never comparable in contrast and sharpness as a native MFT lens and it got even less sharp when attached on the Lens Turbo. Add my misfocusing issues when shooting handheld in real life conditions and the whole "fast combo lens" became a moot point - I could get comparable results with native F2.8 lenses at night. Going wider aperure made depth of field too narrow and made the whole picture too soft even if I got the focus OK. So to ebay the turbo adapter went and I just kept the plain adapter for those nostalgic lens shooting days.

My conclusion is that these adapters are best suited for directed video shooting as critical sharpness is less needed and focus is properly orchestrated and choreographed before shooting so no problem missing it. And it all boils down to how well the chosen lens plays game with the Lens Turbo as the other manual Nikon lenses I had at hand behaved differently as far as frame wide sharpness, vignetting, hot spotting goes and I ended up always wondering how much better would they behave on the proper Speed Booster if I could afford it. Given the various online comparison results I decided to ditch the idea altogether because I do not shoot video and ended up thinking that the combo solution could not get much better to make it worth for my needs. As always, YMMV....

 MichailK's gear list:MichailK's gear list
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buggz Regular Member • Posts: 165
Re: Micro Four Thirds Focal Reducer Shootout

I love my Metabones 0.67 Speedbooster.

All my Canon lenses have worked well for me on both my GH4 and my new GH5.

This includes my tresured 50/1.0L and 200/1.8L

I don't think I'll ever buy a m4/3 lens, definately don't have a need to as I have much EOS mount options available to me.

MOD Tom Caldwell Forum Pro • Posts: 31,591
No issues from me
1

Seems that you make a good case for buying the best and then grumble because something lesser does not come up to scratch.

I am no optical expert but I do believe that the focal reduction can make a good lens work better and the caveat that it can also make the faults of a lesser lens more obvious.

I also find that EF lenses can be focal reduced very effectively to M4/3 with very acceptable AF speed and accuracy.  I have also gone one step further and bought several exotic Sigma DC lenses in EF mount to exclusively use on M4/3.

For some time I have used RJ brand dumb focal reduction adapter from FD and M42 mounts to M4/3 very effectively across a range of very capable legacy MF lenses.

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Tom Caldwell

obsolescence
obsolescence Contributing Member • Posts: 583
Re: Micro Four Thirds Focal Reducer Shootout

@MichailK --

"...it all boils down to how well the chosen lens plays game with the Lens Turbo as the other manual Nikon lenses I had at hand behaved differently as far as frame wide sharpness, vignetting, hot spotting goes and I ended up always wondering how much better would they behave on the proper Speed Booster if I could afford it."

It would be helpful if you would explain which other Nikon lenses you used and how they behaved, if you can remember. If you wondered how well they would behave on the "proper" SB, then perhaps you were dissatisfied with their performance on the LT. I think that specific information about defects or IQ dissatisfaction would be useful to other users. Metabones is the sure bet, but it's not the only solution that can provide high IQ for the type of work in question.

I'm guessing you upgraded to native lenses because you could then afford them and you believed they would be optimal -- which is a reasonable expectation, but not always true. It may depend on how you want to work. Manufacturers of native lenses program their cameras to optimize AF points for each of their lenses and use special algorithms for face recognition and distortion/aberration correction, which make shooting and processing much easier.

Those who prefer to use AF should probably not even consider adapted lenses unless a fully automatic adapter is available (it will be quite costly) and their specific lens AF has been demonstrated to be quick and accurate with the adapter. Some of us (a dwindling few, it seems) do not find manual focus to be a disadvantage for the type of shooting we do, and in some cases it's clearly advantageous, especially for video and with cameras that have magnification and peaking features.

Eric Nepean
Eric Nepean Veteran Member • Posts: 3,118
Re: Micro Four Thirds Focal Reducer Shootout

MichailK wrote:

...just a post for any low production amateurs like me arriving at this thread as they look after the [FocalReducer+OldLens] interesting solution for shooting stills:

My amateurish opinion in short:

1. If you really need a Focal Reducer adapter, get the proper one and be done with it (get the Metabones) and stop mumbling about the price.

2. If you are not sure you really need or fancy such a device, get the much cheaper and 2nd best Zhongyi Lens Turbo, use it for some time and then decide whether to ditch the Focal Reducer idea altogether or to get the proper one (--> Metabones) and be done with "what focal reducer?" so you can concentrate on what lenses work best on it instead of scratching your head when results are found lacking for whatever reason (so do get the focal reducer quality out of the equation by getting the best).

Now, to elaborate more:

I never got any "proper" Metabones Speed Booster since back then I could barely afford a "Zhongyi Lens Turbo II Focal Reducer" for my MFT camera which I used for a few months last year coupled to three Nikon AiS lenses before selling it to fund a native MFT prime lens later on. Most use was with a prime 50mm/1.4 which gave me a nice calculated combo of 36mm/1.0.

What I found out is that the old lenses have their nice "feel" and "manual" fun but lack the sharpness and contrast sparkle that native MFT lenses provide (along modern commodities like autofocus). So for my hands it proved too easy to miss critical focus when using wide apertures and that made me use the Lens Turbo combo less and less over time for whatever intrigues me to take a shot of - I just got too soft results most of the time.

As far as this particular 36/1.0 combo goes, I did some homegrown comparative experiments and found out that the extravagant wide open spherical aberration(?) of the 50/1.4 Ais lens makes it usable for my kind of hobby photography only at narrower aperture than (Fcombo:2.0) and even then the lens turbo adapter robbed some of the already not great sharpness off the 50mm/1.4 lens. That is, this respectable FF 50mm lens at wider aperture than F4.0 on a plain adapter was never comparable in contrast and sharpness as a native MFT lens and it got even less sharp when attached on the Lens Turbo. Add my misfocusing issues when shooting handheld in real life conditions and the whole "fast combo lens" became a moot point - I could get comparable results with native F2.8 lenses at night. Going wider aperure made depth of field too narrow and made the whole picture too soft even if I got the focus OK. So to ebay the turbo adapter went and I just kept the plain adapter for those nostalgic lens shooting days.

My conclusion is that these adapters are best suited for directed video shooting as critical sharpness is less needed and focus is properly orchestrated and choreographed before shooting so no problem missing it. And it all boils down to how well the chosen lens plays game with the Lens Turbo as the other manual Nikon lenses I had at hand behaved differently as far as frame wide sharpness, vignetting, hot spotting goes and I ended up always wondering how much better would they behave on the proper Speed Booster if I could afford it. Given the various online comparison results I decided to ditch the idea altogether because I do not shoot video and ended up thinking that the combo solution could not get much better to make it worth for my needs. As always, YMMV....

I have the oldest M43 to Canon FD mount 0.71x Metabones Speedbooster.

It gives very decent image quality with a FD50mm F1.4 wide open; however IMO wide open the image density behaves as if the combo is F1.1 rather than F1.0 No matter, IMO it's a very nice pieece of kit, and I'm quite happy using it with a variety of FD lenses. The only lens that disappointed is the 28mm F2.8

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Cheers
Eric

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Bhima78 Senior Member • Posts: 2,674
Thanks to whoever Necro'd this thread.

I had never seen this thread before, and I'm glad someone recently posted on this. I wish we had a sticky folder of threads like these.

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MichailK Junior Member • Posts: 31
Re: Micro Four Thirds Focal Reducer Shootout

buggz wrote:

I don't think I'll ever buy a m4/3 lens, definately don't have a need to as I have much EOS mount options available to me.

I am glad for you! My wallet cannot support the Metabones prices so I shall always remain with the question of how much better the Nikon lenses I have could have behaved vs the 2nd best solution I got as a present after much drooling and wishing.

Tom Caldwell wrote:

Seems that you make a good case for buying the best and then grumble because something lesser does not come up to scratch.

It's all a matter of wallet happiness: Last year I was in the "practically zero income" territory so I wanted to get by with the old Nikons handed to me by a friend along the adapter I was gifted after months of wishing to see what I could do with this solution. These days I have something little getting in the wallet each month, I saw that even Sigma cheap native lenses suit my definition of photographic sharpness much better than fighting with the focus and the various idiosyncrasins of the "combo" solution I got. Even if the Metabones product is much better than what I had (judging by the comparative reviews), I doubt that it would cover my needs for my style of the little shooting I occasionally do with what I have at hand.

I am no optical expert but I do believe that the focal reduction can make a good lens work better and the caveat that it can also make the faults of a lesser lens more obvious.

I also read the Brian Caldwell's white paper and I could never doubt all the work and samples presented by serious sources on the matter neither would I want, be able or dispute the value of the offered solution. What I report was my experience mostly on an immaculate Nikon 50mm/1.4 Ai-S which I understand is a good enough lens to be sold by Nikon until these days since 1981, mounted on the not-Metabones adapter I could source.

I also find that EF lenses can be focal reduced very effectively to M4/3 with very acceptable AF speed and accuracy. I have also gone one step further and bought several exotic Sigma DC lenses in EF mount to exclusively use on M4/3.

For some time I have used RJ brand dumb focal reduction adapter from FD and M42 mounts to M4/3 very effectively across a range of very capable legacy MF lenses.

I have no doubt you are many times more worthy a "Photographer" than me (no irony) - I mostly refer to myself as a Scotographer and maybe sometime I will graduate to the Photographer designation even though I no longer do much of night shots. However, my low yield photography hobby matters a lot to me and my Zhongyi Lens Turbo despite its excellent value for money built qualities just didn't cut it in my hands given the lenses I have at hand.

obsolescence wrote:

It would be helpful if you would explain which other Nikon lenses you used and how they behaved, if you can remember.

I used mostly the classic(?) 50mm/1.4 Ai-s of 1981 still on sale by Nikon - mine (really belonging to a friend) is an immaculate late '80s copy. Some use was with a 28-85mm/3.5-4.5 AF-S (not Ai-S), little use with a 25-50mm/4 Ai-s (landscape use special), and just for testing use with a 500mm/8 mirror lens (technically an Ai? not -s).

Looking back I saw I kept too few pictures with the Lens Turbo as they mostly lacked mostly in sharpness qualities and the lack of metadata makes it difficult judging which photo came from which lens with or without the adapter.

Maybe I should finally setup a gallery for dpreview forum use like this thread - I generally do not post pictures unless needed to be used in some motorcycling forum I participate.

Let me some days to look into it as I have various troubles at home these days.

Eric Nepean wrote:

I have the oldest M43 to Canon FD mount 0.71x Metabones Speedbooster.

It gives very decent image quality with a FD50mm F1.4 wide open; however IMO wide open the image density behaves as if the combo is F1.1 rather than F1.0

the Zhongyi Lens Turbo on my 50mm/1.4 went down to something like 1.2 when wide open instead of 1.0 according to my E-PL5 metering which I guess is pixel vignetting - fast enough as I could shoot handheld in conditions I could barely see the subject's figure but the outcome despite artistically beautiful to my eyes was a seldom success and in no way "sharp" as I wished it to be - too much of a chore for me, I decided in the end, threw away most of the few shots and used the combo less and less ....

Bhima78 wrote:

I had never seen this thread before, and I'm glad someone recently posted on this. I wish we had a sticky folder of threads like these.

I am glad I did something good for someone even if all my reported data may be of little real value given the lack of objective measurements - I do not consider my comparative shots of a fine texture textile worth posting since the whole setup was too makeshift to be objectively foolproof (where fool read, ahem, me...)

 MichailK's gear list:MichailK's gear list
Olympus PEN E-PL5 Olympus M.Zuiko Digital 14-42mm 1:3.5-5.6 II R Sigma 19mm F2.8 DN | A Sigma 60mm F2.8 DN Art Olympus M.Zuiko ED 75-300mm 1:4.8-6.7 II +6 more
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