Using a speedbooster and its impact on image quality.

[jrharvey592]

Hey guys... I heard mixed things all over the place about how using a speedbooster impacts image quality and most of the concensous was that it would negatively impact the quality due to adding more glass elements into the mix. Decided to do my own test with and without a speedbooster and was kinda shocked to see the opposite.

Here is some tests using the G9 (WATCH IN 4K)

https://www.youtube.com/watch?v=IlxHwLCQ9no

Of course this is using adapted cannon lenses so keep in mind that micro 4/3 native glass is going to be designed specifically for the smaller sensors and give sharper results than adapted full frame lenses. Its interesting to see though. Tried some full frame rokinon lenses but also the Sigma Art 18-35 which is designed to be sharp on APS-C and even that shows a noticable increase in quality when using the speedbooster.

I didnt see a lot of info out there on the internet that talks about the increase in quality so thought Id put this out there.

 

[Mark9473]

Hey guys... I heard mixed things all over the place about how using a speedbooster impacts image quality and most of the concensous was that it would negatively impact the quality

Let me guess, opinions from people that haven't used adapted lenses?

I didnt see a lot of info out there on the internet that talks about the increase in quality so thought Id put this out there.

There's quite some documentation here on DPR as well as on PetaPixel, if you do a search. Thanks for adding to that.

 

[Astrotripper]

Hey guys... I heard mixed things all over the place about how using a speedbooster impacts image quality and most of the concensous was that it would negatively impact the quality due to adding more glass elements into the mix. Decided to do my own test with and without a speedbooster and was kinda shocked to see the opposite.

It's not a surprise to people familiar with Metabones SpeedBoosters and what the optics in those adapters does.
Of course, most if not all cheapo focal reducers will indeed cause reduction in image quality.

 

[Alan_W1]

Looks good, and shows the improvement nicely.

I don't have a metabones, but recently bought a cheaper Viltrox NF-M43, and although I haven't done any critical testing, I recently grabbed a quick real-world comparison "in the field" and can't detect any noticeable degrading with the specific lens I was using....compared to the bare lens only {which was my minimum hope with this cheap'ish focal reducer}, and suspect it too gives an improvement in quality in the circumstances I use this combination in.

I did post the images of my Viltrox comparison recently, but forgot to turn off the software's default noise reduction/correct WB etc....so below is a more realistic comparison.

To my eye there is no noticable degrading with the Viltrox, and had I had the opportunity to reduce my shooting distance with the Viltrox image, and therefore equalise the subject size { which is how I use this adapter in the field}, then I suspect there will indeed be an effective IQ gain with this specific Focal Reducer/lens combo too.

It seems likely that a metabones {given the price} would give a touch more quality, but I think for my outdoor/telephoto video purposes this cheaper Viltrox is a very good performer.

When I get some time, I may try a more stringent comparison {maybe indoors with a shorter lens and closer shooting distance}, just to confirm my suspicions...or not.


Panasonic g80 / Nikkor 400mm f3.5 @ f4


as above plus Viltrox nf-m43x 0.71

Both taken at approx. 18 meters with camera sharpness setting at -5, and Silkypix software set to Natural sharpening on both examples. No CA correction or noise reduction applied.

 

[David Kieltyka]

The Yashica/Contax Speedbooster genuinely improves the performance of Y/C lenses on my GX8. The shorter focal lengths in particular not only give me wider coverage due to the SB optics but are also sharper into the corners than when used sans SB.

-Dave-

 

[hindesite]

There's quite a lot of coverage of how IQ is affected, and in general it is either improved or the reduction in IQ is not so bad that the other benefits are outweighed.

I have a Zhongyi Turbo II and in general it works absolutely fine.

However, how it performs with specific lenses is a wildly mixed bag and very unpredictable. Some lenses that perform very well with a straight adapter don't always perform well on the reducer. Some lenses that are not great on straight adapters are dramatically improved, and surprisingly, some of these are zooms.

 

[jrharvey592]

Interesting. I swear I must have watched 100 reviews on speedboosters and pretty much every time people said that it reduces sharpness and increases CA. Haha so weird. Maybe those people never actually tested it lol.

 

[Sergey Borachev]

Interesting. I swear I must have watched 100 reviews on speedboosters and pretty much every time people said that it reduces sharpness and increases CA. Haha so weird. Maybe those people never actually tested it lol.

I suspect some of those testers did not do very valid tests or not even realise that the effects from speed boosting cannot be just compared independently of the change in light gathered, FOV, etc, ie not comparing equal with equal, like edge sharpness with edge sharpness.

 

[bluehighwayman]

I had some OM lenses and decided to buy a speedboster. I got the Kipon .7x and Metabones .71 om to M4/3 to compare them. Two of the OM lenses wouldn't even fit on the Metabones but all fit on the Kipon. After some testing I found the Metabones to be ever so slightly better than the Kipon but it was really a hairsplitter. They both did way better than a plain adaptor both increasing the brightness and sharpness of the OM lenses. The Metabones cost $449 USD and the Kipon $160 USD so the Kipon was the keeper considering the bang for the buck. The only problem I have now is wanting to buy a few more OM lenses instead of M4/3 ones. Especially for low light shooting as the speedbooster gives the lens a +1 stop ie f/2.8 becomes f/2.0

 

[Tom Caldwell]

You should read the Metabones White Paper which discusses the effects of focal reduction in an unbiased technical manner:

http://www.metabones.com/assets/a/stories/Speed Booster White Paper.pdf

Hey guys... I heard mixed things all over the place about how using a speedbooster impacts image quality and most of the concensous was that it would negatively impact the quality due to adding more glass elements into the mix.

No such thing as “a consensus”. Focal reduction acts in the opposite manner to teleconversion (which does reduce image quality to get more magnification). Therefore such a consensus is no more than confused thinking. Many current model lenses such as retrofocal design and wide angle have a huge number of lens elements in them and are in fact excellent lenses - whereas the same sort of thinking would have doublets (two lenses) or triplets (three lenses) as the prefect lens.

Decided to do my own test with and without a speedbooster and was kinda shocked to see the opposite.

No need to be shocked.

Here is some tests using the G9 (WATCH IN 4K)

Of course this is using adapted cannon lenses so keep in mind that micro 4/3 native glass is going to be designed specifically for the smaller sensors and give sharper results than adapted full frame lenses.

Not necessarily so - there is no doubt that a M4/3 lens is designed for the sensor in question and that can give advantages but a FF EF mount lens that is sharp on a larger sensor should ahve every capability of being sharp on a smaller sensor as well.

Its interesting to see though. Tried some full frame rokinon lenses but also the Sigma Art 18-35 which is designed to be sharp on APS-C and even that shows a noticable increase in quality when using the speedbooster.

I didnt see a lot of info out there on the internet that talks about the increase in quality so thought Id put this out there.

See the Metabones White Paper linked above - there would also be other similar information available.

--
Tom Caldwell

 

[Tom Caldwell]

Hey guys... I heard mixed things all over the place about how using a speedbooster impacts image quality and most of the concensous was that it would negatively impact the quality due to adding more glass elements into the mix. Decided to do my own test with and without a speedbooster and was kinda shocked to see the opposite.

It's not a surprise to people familiar with Metabones SpeedBoosters and what the optics in those adapters does.

Of course, most if not all cheapo focal reducers will indeed cause reduction in image quality.

Of course there are good and better focal reduction adapters and Metabones could well hold the prize for the best in the business. But the Metabones White Paper tends to indicate that all focal reduction adapters will improve the image - merely by compressing the image on to a smaller area.

I have not noticed focal reduction adapters actually reducing image quality as such but it is also well known that lens aberrations can also be accentuated by the focal reduction effect.

Brian Caldwell (no relation, no commercial connection) has stated that his Ultra design for focal reduction adapters will improve the image quality of all lenses that they are adapted with - I have no reason to doubt his claim.

 

[PhotoTurtle]

Hey guys... I heard mixed things all over the place about how using a speedbooster impacts image quality and most of the concensous was that it would negatively impact the quality due to adding more glass elements into the mix. Decided to do my own test with and without a speedbooster and was kinda shocked to see the opposite.

Here is some tests using the G9 (WATCH IN 4K)

Of course this is using adapted cannon lenses so keep in mind that micro 4/3 native glass is going to be designed specifically for the smaller sensors and give sharper results than adapted full frame lenses. Its interesting to see though. Tried some full frame rokinon lenses but also the Sigma Art 18-35 which is designed to be sharp on APS-C and even that shows a noticable increase in quality when using the speedbooster.

I didnt see a lot of info out there on the internet that talks about the increase in quality so thought Id put this out there.

That's rather bizarre. Essentially this boils down to "take an image and squeeze it into a smaller space = brighter and sharper image", as long as some care is taken to make the optics be of reasonable good quality so as not to mess up this natural physical phenomenon.

I had heard the opposite of what you heard online when the Speedboosters first came out. From what I recall, some people did actual tests on MTF machines (?) and proved that they improved the MTF numbers of the lenses.

A lot of people were doubtful at the time because they just couldn't wrap their head around the never-before-seen concept of improving a lens by adding an optical adapter. I suspect that the negative reviews were just people stuck with preconceived biases and who would literally just not believe their eyes because it couldn't be possible. Either that, or what someone else here mentioned that some lenses perform better than others with focal reducers.

 

[JakeJY]

The logic is you are squeezing the light into a smaller area, which increase the MTF and quality. However, the lens tested and the speedbooster used does matter.

I find this comparison very useful:

https://www.dpreview.com/forums/thread/3627547

Other than the worst one (light cannon with single element), most of them do fine in the center, but corner and edges suffer in the others.

 

[JakeJY]

The logic for a speedbooster improving quality is it squeezing the light into a smaller area and Metabones also claims to account for the sensor glass thickness.

However, the quality still varies depending on what lens and type of speedbooster.

I find the shootout linked telling. The single element one does bad in all cases. The others all do decent in the center (perhaps sharpness is better than bare lens), but on the corners and edges some do worse.

https://www.dpreview.com/forums/thread/3627547

 

[bluehighwayman]

Here are some photos using the Kipon .7x OM to M4/3 Speedbooster with a Tokina 35-105 f/3.5-4.5 which becomes a 49-147 f2.5-3.2 (?). The Kipon has a max f-stop pass through of 1.4 but the Metabones I think goes down to f/.95. Yes I was at the farm stand!

 

[hindesite]

The Yashica/Contax Speedbooster genuinely improves the performance of Y/C lenses on my GX8. The shorter focal lengths in particular not only give me wider coverage due to the SB optics but are also sharper into the corners than when used sans SB.

-Dave-

I see the same with my 17/3.5 Nikon mount Tokina. Used straight it is quite soft in the corners, and has to be stopped down a lot to get sharpness everywhere; with the focal reducer the improvement is dramatic - and wider, too.

 

[Jan Steinman]

I had some OM lenses and decided to buy a speedboster. I got the Kipon .7x and Metabones .71 om to M4/3 to compare them. Two of the OM lenses wouldn't even fit on the Metabones…

In my experience, this is solely because of a thin bit of metal that Olympus put on many of their lenses. It protrudes out the back, around the rear lens element, at the bottom of the lens, where it would not impact mirror swing.

The only reason for this bit of metal that I can discern is it protects the rear element if one is foolish enough to put your lens, without cap, rear-element down. I don't think many people would do that!

I've removed this metal on many OM film lenses.

The first was a beloved 90mm ƒ/2 macro. I carefully padded the rear element, put some cardboard over the padding, and taped it to the lens with painters' ("blue") tape. I then covered the rest of the lens with a plastic bag, and taped that shut. I then carefully use a file, one stroke at a time, and removed the tab. It took about an hour.

The second was a beloved 21mm ƒ/2 super wide. I grabbed one end of the tab with thin pliers, and twisted the tab off like a sardine lid. It took maybe ten minutes.

So now I use the second technique on any OM lens I get that has that stupid tab on it, and they all fit the Metabones that way.

 

[Jan Steinman]

Of course, most if not all cheapo focal reducers will indeed cause reduction in image quality.

I have not noticed focal reduction adapters actually reducing image quality as such…

Brian Caldwell (no relation, no commercial connection) has stated that his Ultra design for focal reduction adapters will improve the image quality of all lenses that they are adapted with - I have no reason to doubt his claim.

I don't doubt his claim, either!

But that's not to say that it is impossible to build a crappy focal reducer.

The first one I ever bought was like smearing Vasoline™ on a lens! But it was only $60, and I deserved those nasty results for pinching pennies.

 

[3dpan]

Of course, most if not all cheapo focal reducers will indeed cause reduction in image quality.

I have not noticed focal reduction adapters actually reducing image quality as such…

Brian Caldwell (no relation, no commercial connection) has stated that his Ultra design for focal reduction adapters will improve the image quality of all lenses that they are adapted with - I have no reason to doubt his claim.

I don't doubt his claim, either!

But that's not to say that it is impossible to build a crappy focal reducer.

The first one I ever bought was like smearing Vasoline™ on a lens! But it was only $60, and I deserved those nasty results for pinching pennies.

My experience involves using a Viltrox Speedbooster for astrophotography.

A star field is a very severe test of a lens "IQ".

I found that the Viltrox introduced tangential astigmatism to lenses 135mm and shorter.
Specifically
(i) Samyang 135/2
(ii) Olympus 100/2
(iii) Samyang XP 35/1.4

Longer lenses eg Nikon 180/2.8 D and Zeiss Mirotar 500/8 did not show any tangential astihmatism.

I raised the question with Metabones, does their Speedbooster exhibit the same affect ? and sent them example images.

No reply after two years so I assume they don't know/don't care.

 

[Mark9473]

My experience involves using a Viltrox Speedbooster for astrophotography.

A star field is a very severe test of a lens "IQ".

I found that the Viltrox introduced tangential astigmatism to lenses 135mm and shorter.
Specifically
(i) Samyang 135/2
(ii) Olympus 100/2
(iii) Samyang XP 35/1.4

Longer lenses eg Nikon 180/2.8 D and Zeiss Mirotar 500/8 did not show any tangential astihmatism.

I think this proves that the astigmatism is in the shorter lenses and not in the adapter. Which is also what would be expected - have you tried those lenses with an adpeter without optics in it?

I raised the question with Metabones, does their Speedbooster exhibit the same affect ? and sent them example images.

No reply after two years so I assume they don't know/don't care.