My thoughts on the Kipon Medium Format "Speedbooster"

[jcs]

1 minute ago, tweak said:

"Equivalence" is relative, relativity is based on perspective, I feel this is where the problem lies.

Equivalence is math & physics. That is where the problem lies...

[tweak]

Just now, jcs said:

Equivalence is math & physics. That is where the problem lies...

hahaha true.

[jcs]

5 minutes ago, tweak said:

hahaha true.

So if we focus on the art, the emotion of the combined 'lens filter', we can categorize looks so others can replicate themselves* and quit arguing about sensor size. I think Mattias' pics look cool, and if a MF->FF focal reducer plus cheap MF lenses can be used to recreate those looks, that's pretty neat- gives new love to neglected unused MF lenses

 

* this was not meant as a cloning comment  

[tweak]

7 minutes ago, jcs said:

So if we focus on the art, the emotion of the combined 'lens filter', we can categorize looks so others can replicate themselves* and quit arguing about sensor size. I think Mattias' pics look cool, and if a MF->FF focal reducer plus cheap MF lenses can be used to recreate those looks, that's pretty neat- gives new love to neglected unused MF lenses

 

* this was not meant as a cloning comment  

We're on the same page.

[Mattias Burling]

Sweden is a great place for camera nerds in the summer when the sun never sets and the golden hour lats for ever. The winter is of course the opposite.
So when I come home from work I can usually see a sunset but then its lowlight photo or no light photo.

But I can at least take indoor shots to test my second Mamiya 80mm f1.9 that arrived today.
We have a service here where one can return items for a full refund within 24h when buying used stuff from regular people online. 
So light or no light, I needed to test it.

The lens was in great shape.

Its of course bigger than a f2.8 version but with the adapter its never gonna be a pancake anyway.

Both shots are f1.9 because.. you know... it can.
That of course means not the maximum amount of sharpness. But I still really like the detail without looking "too digital" if you know what I mean.

I like how when zooming in I can see that GP had a hair stuck in her mouth that goes in and out of focus on its way down to the bed spread. 

[tupp]

On 2/27/2017 at 1:56 AM, Brian Caldwell said:

You are expecting a level of precision in this comparison that is entirely unreasonable.

No.  I am expecting those who think that these equivalence tests prove equivalence to simply face the results.

 

On 2/27/2017 at 1:56 AM, Brian Caldwell said:

Little things like changes in distortion and entrance pupil position during zooming make it impractical to make a blink comparator test completely perfect.

In the first place, the results of the three equivalence comparisons are FAR from perfect.  The differences in DOF are quite obvious, especially if one takes the original images and compares them in an image viewer/editor.   The equivalence conclusions from these tests do not stand up to scrutiny.  The erroneous results can't be dismissed from lack of precision.

 

Secondly, would you say that, generally, there is a difference in the prevalence/susceptiblity of distortion between lenses made for smaller formats compared to lenses made for larger formats.  Would you say that there is, generally, an overall difference in entrance pupil position between lenses made for smaller formats compared to lenses made for larger formats.

 

On 2/27/2017 at 1:56 AM, Brian Caldwell said:

What the comparison does show - with more than sufficient precision - is that you can optically reproduce all aspects of an image shot on a large format with one shot on a smaller format - or vice versa.  

No, the comparison in question does not show that -- it anything shows the exact opposite:  the DOF is significantly different between the two images, hence DOF equivalence fails in that test.

 

Furthermore, the other two linked comparisons show even more severe differences in DOF.  Please also address the precision on those two tests.

 

On 2/27/2017 at 1:56 AM, Brian Caldwell said:

The notion that, say, an 80mm medium format lens has some inherent "80mm-ness" or "medium formatishness" that somehow stays with that lens after you attach a focal reducer is just silliness.

Really?  Every test that I have seen intended to demonstrate the notion of equivalence has failed.  Perhaps someone could prove equivalence with a proper test with higher precision.

 

 

On 2/27/2017 at 1:56 AM, Brian Caldwell said:

The combination of a 0.7x focal reducer and an 80mm lens is a 56mm lens.  Period.  Put that 56mm lens on a 24x36mm format camera and it will behave just like any other 56mm lens attached to that camera

The equivalence principle isn't supposed to apply solely to lens/focal-reducer combinations -- it is primarily supposed to apply to prime lenses.

 

On the other hand, the images from this Kipon medium format focal reducer look spectacularly different to an "equivalent" lens made for the 16mm format.

 

 

 

[Laurier]

I had one with a set of mamiya on a a7s, sold it quickly.

First the focal reducer add a fair amount of barrel distortion,
Second, as stated by others, focal reducer.... reduce focal so your 80mm 2.8 become a 56 mm f2.... It s not so exciting, you can t go super wide either .
The only good point for me was that the lenses where bigger with a good focus throw, so quite production friendly.

Due to the modern market full frame lenses got a lot of improvement compared to medium format, today you can get pin sharp lenses wide open at 1.4, so getting medium format glass with a speedbooster on full frame is not such a good idea IMO. 

Using it without can be decent as you only use the center of the image circle but you will be mostly stuck at F2.8.

Keep in mind that the alexa 65 sensor size is not far off full frame either.

If you want the medium format feel on smaller format, just use lenses a bit longer and faster than you are use to, something like the Nikon 105 f1.4 

[tupp]

On 2/27/2017 at 3:03 PM, jcs said:

This discussion reminds me of similar ones for analog vs. digital audio, vinyl/tape vs. digital, tubes vs. MOSFETs, one preamp vs. another preamp, one mic vs. another, crisp and clinical vs. warm and creamy, etc. Head on over to GearSlutz for a taste of audio drama for those inclined: https://www.gearslutz.com/board/ (around 10 million posts!). It's a great resource for audio related questions for filmmaking too.

In agreement with what @Brian Caldwell just said- these lens combos are creating interesting character, analog optical filters (transfer functions), which is art, and that is cool. It has nothing to do with sensor size per se, only the combination of optics to get the desired (or discovered!) look.

Here's an example of Shane Hurlbut comparing Leica Summicron-C to Cooke S4, same sensor size (Super35), and getting vastly different results (his perception, some of you may even disagree with his results):

http://www.thehurlblog.com/lens-tests-leica-summicron-c-vs-cooke-s4-film-education/

To wrap it all up:

Leica Summicron-C Lenses:

• Flatter image
• Makes Monette look more sophisticated and older
• Makes her look wider than the Cooke S4
• More of a white out with lens flares; doesn’t do as well as the Cooke S4 with lens flares.
• Bokeh less stop signing, more round
• Neutral lens
• Less detail in her face
• Doesn’t hold highlights as well as Cooke S4
• Less contrast
   

Cooke S4 Lenses:

• More three dimensional quality
• Makes Monette look younger
• Makes her look skinnier
• Better with lens flares than the Summicron-C lenses
• Slightly more yellow than the Summicron-C
• Bokeh has more of a stop signing effect
• More detail in her face
• Holds highlights more than the Summicron lenses
• More contrast

Thanks @bunk for creating these excellent computer renderings, which physically simulate perfect lenses and sensors via ray tracing photon paths for different sensor sizes and using perfect mathematical equivalence with pixel perfect results:

http://www.eoshd.com/comments/topic/20975-full-frame-aesthetic/?do=findComment&comment=167154

@Mattias Burling offered $100 if the images matched perfectly (if I read the thread correctly, see link above). Mattias did you pay bunk? The time and effort to set up and render those examples was worth way more than $100, and should end any further arguments regarding sensor size for anyone interested in a scientific and rational discussion (bunk also included the Cinema 4D project files for anyone to replicate as per the Scientific Method). @gatopardo replicated the results with VRay (another photon ray tracer) and 3DSMax.

Mattias' comments on medium format lenses being very cheap and 'free' in some cases is very useful information for those admiring the kinds of looks possible with a focal reducer and old medium format lenses, which create interesting analog filters which a lot of people love. As noted by Hurlbut and others, the Cooke S4 causes distortion and has other artifacts which make people look thinner, more 3D, better highlights, etc. Imperfection is the spice of art- makes the flavor interesting which will be loved by many where different forms of spice will be loved by others (or for some uses, no spice at all- clinically accurate (Sony/Zeiss for example)). Like comparing Neve/Avalon preamps (warm/colored) to Grace (clinically clean). Neither better than the other, chocolate vs. vanilla...

A simulation is not reality.  Furthermore, does this simulation take into account variables of diffraction and of the variable concerning general differences between lenses made for small formats and lenses made for larger formats (such as flatness of field)?

[Laurier]

7 minutes ago, tupp said:

A simulation is not reality.  Furthermore, does this simulation take into account variables of diffraction and of the variable concerning general differences between lenses made for small formats and lenses made for larger formats (such as flatness of field)?

Well perspective compression is relative to your distance to your subject ( that why people speak about equivalence , a 42.5 on micro four third and a 85mm on full frame will produce the same compression at the same distance from the subject) 

The test you show simply say that the Leica are more corrected in term of distortion than the Cooke.

If you like distortion, get the Kippon, you will get a lot of it. But in term of compression and dof your 80mm f 2.8 will act like a 52mm f 2 .

The point of larger format is I guess that wide angle are a bit easier to manufacture.

[Mattias Burling]

My 50mm primes or zooms definitely don't have the rendition of the Mamiya + Adapter. So IMO its very exciting. Its medium Format.
In short, I'm blown away by the look and detail.

 

(the adapter and MF lenses also seems to have way less aberration than my modern lenses, but I need to test it more to confirm.)

[jcs]

1 hour ago, tupp said:

A simulation is not reality.  Furthermore, does this simulation take into account variables of diffraction and of the variable concerning general differences between lenses made for small formats and lenses made for larger formats (such as flatness of field)?

Simulation is not reality-  are you sure about that? https://www.theguardian.com/technology/2016/oct/11/simulated-world-elon-musk-the-matrix (ever wonder why quantum physics is... quantized or why the Planck length exists? I'm a bit uncertain, maybe we can ask Heisenberg).

Sure, simulations can do diffraction: https://docs.chaosgroup.com/display/VRAY3MAX/Lens+Effects, and Cinema 4D also does quadratic and cubic distortion as well as chromatic aberration. I've written a few simulators, flight and racing, and from the math it's clear we can simulate anything. Simulations are approximations, and as the approximations approach reality, computational time increases. At the limit we could perfectly simulate reality (that's where the Simulation Hypothesis comes from in the link above). Would it be exactly the same as this reality, say to recreate something in this reality in a simulation? Nope, Heisenberg will tell you why. So we can avoid that argument, right?

I'm just a software guy into filmmaking and lately metaphysics. @Brian Caldwell is a lens designer and is perhaps the best resource who posts on this forum regarding real world optics. He created the SpeedBooster of which the Kipon is a kind of copy. Hey, if you're still not convinced, well, we can all agree that the art created by these devices is cool!  

[tweak]

I think what people fail to realise here is that for most people using MF lenses (or any vintage lens) I'm sure has nothing to do with whether you can get other "equivalent" lenses to match or do an "equivalent" job... it's all about the things that aren't supposed to be there, the "mistakes" if you will that make the image interesting. It's like playing music, jazz as an example, the notes you don't play and the unexpected notes you do play make what you are doing interesting to some people. If you just played a super predictable structured melody I don't know many musicians personally who would be overly impressed...
That being said not everyone may enjoy what you are doing (they never will in life) but if something has worth and merit to you don't let anyone tell you otherwise.

I will give you the big secret, everything you do in your day to day life is pointless, in fact life is pointless. There's no plan waiting for you at the end, no one there to pat you on the back and tell you did life right. Just do what makes you happy and help others where you can  .

[Mattias Burling]

9 minutes ago, tweak said:

I will give you the big secret, everything you do in your day to day life is pointless, in fact life is pointless. There's no plan waiting for you at the end, no one there to pat you on the back and tell you did life right. Just do what makes you happy and help others where you can  .

This.

[jcs]

19 minutes ago, tweak said:

I will give you the big secret, everything you do in your day to day life is pointless, in fact life is pointless. There's no plan waiting for you at the end, no one there to pat you on the back and tell you did life right. Just do what makes you happy and help others where you can  .

Each of us runs a local simulation of reality- there can be a point if you want, or not. We are all the same

[tweak]

13 minutes ago, jcs said:

Each of us runs a local simulation of reality- there can be a point if you want, or not. We are all the same

It's a good theory, everything is a good theory.

[noone]

2 hours ago, Laurier said:

2 hours ago, Laurier said:

Well perspective compression is relative to your distance to your subject ( that why people speak about equivalence , a 42.5 on micro four third and a 85mm on full frame will produce the same compression at the same distance from the subject) 

The test you show simply say that the Leica are more corrected in term of distortion than the Cooke.

If you like distortion, get the Kippon, you will get a lot of it. But in term of compression and dof your 80mm f 2.8 will act like a 52mm f 2 .

The point of larger format is I guess that wide angle are a bit easier to manufacture.

Well perspective compression is relative to your distance to your subject ( that why people speak about equivalence , a 42.5 on micro four third and a 85mm on full frame will produce the same compression at the same distance from the subject) 

The test you show simply say that the Leica are more corrected in term of distortion than the Cooke.

If you like distortion, get the Kippon, you will get a lot of it. But in term of compression and dof your 80mm f 2.8 will act like a 52mm f 2 .

The point of larger format is I guess that wide angle are a bit easier to manufacture.

That reminds me.

When the Kipon m4/3 smart adapter (not a focal reducer) for EF lenses was first released, it had bad distortion (and other issues) but after a few firmware updates, it is just fine and the distortion issue is a thing of the past.

I don't think it is necessarily a focal reducer issue as opposed to a design issue.

To me, focal reducers are simply tools that allow access to more lenses and are particularly useful when there are no or few lenses of a particular type for a given camera.

There is much less need in using medium format lenses on a FF sensor as there is so much choice available.

I don't get the argument about different look generally as all lenses are different even for the same format.

Maybe if you have a lens designed as a wide angle for one system that becomes telephoto on another there might be some issue of distortion (from lens design not perspective) IE maybe a 15mm FF lens on a Pentax Q?

That said, I do like what Mattias is doing anyway from the results.

[tweak]

4 minutes ago, noone said:

I don't get the argument about different look generally as all lenses are different even for the same format.

I don't understand the argument generally but I do understand it in some cases.

[noone]

4 minutes ago, tweak said:

I don't understand the argument generally but I do understand it in some cases.

Yeah, sorry!   Probably  should read "don't get the argument about a different look between a lens for one format with a focal reducer on a smaller format against one made for that format as most lenses are different even within the same format. "    Or something like that.

[tweak]

3 minutes ago, noone said:

Yeah, sorry!   Probably  should read "don't get the argument about a different look between a lens for one format with a focal reducer on a smaller format against one made for that format as most lenses are different even within the same format. "    Or something like that.

To me this would still mean the same thing.

The two are just different levels of the same principle, it makes as much sense to do either or as is your perceived return from doing so. If you see no intrinsic value in using a speed boosted lens on a smaller format then logically it would make little sense for you to do it. If you see some worth or value in using a speed boosted lens then it makes as much sense as using any native lens for similar reasons.

 

[noone]

12 minutes ago, tweak said:

To me this would still mean the same thing.

The two are just different levels of the same principle, it makes as much sense to do either or as is your perceived return from doing so. If you see no intrinsic value in using a speed boosted lens on a smaller format then logically it would make little sense for you to do it. If you see some worth or value in using a speed boosted lens then it makes as much sense as using any native lens for similar reasons.

 

I guess I just don't look on a focal reducer to give a Medium format "look" on FF or FF on APSC or APSC or FF lenses on M4/3 ETC.

You are not changing anything to do with the Camera but you are changing the lens.

I would love a M4/3 Speedbooster to use my Canon lenses on my GX7 but am fine with the non focal reducer Kipon adapter and when I do want a focal reducer I do have a first gen Lens Turbo but being a "dumb" adapter, I can only use my lenses wide open and some I can not focus (some can).     I like that the lenses get a speed boost and sometimes want the shorter focal length but it is not changing the GX7 to a APSC camera.

I also have the wretched Light Cannon with Nikon lenses on my M4/3.     Now there is a device that can put people off focal reducers forever!

Got it very cheap just to see if it had any redeeming features or use when it was being sold as a "soft focus" adapter- maybe it does but I have not found a situation to use it yet really.

I wanted to try and fit a M4/3 focal reducer to my A7s via the thin M4/3 to Sony E adapter to experiment but the focal reducers don't fit in the adapter.