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My thoughts on the Kipon Medium Format "Speedbooster"


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1 hour ago, Viscount Omega said:

Not if I'm shooting on film.   The point is that you can have two camera set-ups in the same position with the same field of view and two different focal lengths

All yeses so far!!!

1 hour ago, Viscount Omega said:

and two different perspectives. 

No, that's not possible. The only thing that influences perspective is subject distance. If the image circle is smaller or larger you get less or more vignetting, respectively, for a given format. Perspective doesn't change, not even if you add an anamorphic adapter. You're probably misunderstanding the term "perspective" - it has to do with the spatial relationship between objects in the scene. It can only be altered by moving objects, or moving the camera. 

 

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When this thing was announced it totally blew my mind. And I have been wanting one ever since the first time I read about it. If you don’t know what this is all about just think of it as a Spee

Do the experiment properly and you'll find that the perspective is the same.  Surely you must have heard countless times before that perspective depends only on the subject distance.  This is a truth

Even crappy jpegs look decent pretty much straight from camera.

Posted Images

10 hours ago, tweak said:

Exactly. As was happening here (or people assumed was happening ;) ).

You assumed they were, yes. But as I've pointed out "Look" is a very ambiguous word, open for interpretation, not definitive to your arguments in this thread which are that of equivalency and math/ science of sensor size vs DOF. Others (like me) I assume to actually be talking about "look" in regards to the lenses and the characteristics of such used on different sensor sizes. Thus to argue there is no different "look" between lenses for different formats imo would be to argue there is no different look between any lenses at all...

'Look' works as it captures any possible effect at all. The argument has been: does sensor size, by itself, create any specific visual effect or look, whatsoever, or not.

Do lenses made for different formats have any special characteristics related to the intended capture format? One could argue size, however some full frame lenses are bigger than some medium format lenses. I had asked Brian Caldwell if he'd be making a medium format Speed Booster and he said no. There are now many very high quality full frame lenses and medium format lenses have no unique properties, so there was no point. A lens is defined by its optical transfer function, that's it.

In this thread we learned that some medium format lenses can be found for very low cost. Combined with a focal reducer for full frame bodies that provides a cost effective way to get shallow depth of field, swirly bokeh, or other desired artistic looks. That's cool and useful info, thanks again @Mattias Burling!

In summary, what we have been discussing is the notion that any format has any special and unique look or characteristic: 'full frame look' and 'medium format look' really mean a 'shallow depth of field look' or in some cases 'swirly bokeh' or other lens artifacts, which aren't specific to any sensor size or any lenses designed for a specific format.

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9 hours ago, kaylee said:

"Theatricality and deception... powerful tools to the uninitiated"

idek why nolan shot any of that movie on 70mm since its the same smh

70mm film (actually 65mm, 70mm is marketing) provides a lot more resolution, so the projected image can be much bigger. Nothing special about the look other than marketing :P

I watched Interstellar in 70mm and it was kind of a mess (Chinese theater in Hollywood), with lots of blurry shots and overall not very sharp (+ sound was way too high and distorted). The 35mm shots were glaringly too sharp when they cut in. A while later I watched Interstellar again in 4K digital (AMC Century City) and it looked more consistent (maybe it was a new edit- they had fixed the sound problem). 70mm is a marketing term, generally telling us to expect a giant, high resolution screen (they may imply a special magical look, however that's just marketing going after your money).

The ARRI 65 is 3 ALEV III sensors rotated 90 degrees (A3X). This also provides a major boost in resolution. The ARRI look is at least partly due to the ALEV III sensor, and making one higher resolution with smaller pixels while maintaining the same look is likely challenging (though they may have solved it by NAB for a (true) 4K+ Alexa announcement).

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1 hour ago, hyalinejim said:

All yeses so far!!!

No, that's not possible. The only thing that influences perspective is subject distance. If the image circle is smaller or larger you get less or more vignetting, respectively, for a given format. Perspective doesn't change, not even if you add an anamorphic adapter. You're probably misunderstanding the term "perspective" - it has to do with the spatial relationship between objects in the scene. It can only be altered by moving objects, or moving the camera. 

"No, that's not possible. The only thing that influences perspective is subject distance."

Because you declare it so?

"If the image circle is smaller or larger you get less or more vignetting, respectively, for a given format."

LOL. Just LOL.  Yeah, that's all it is.  F-----g preposterous.

"Perspective doesn't change, not even if you add an anamorphic adapter. You're probably misunderstanding the term "perspective" - it has to do with the spatial relationship between objects in the scene."

That's exactly what I mean--the spatial relationship between objects.

"It can only be altered by moving objects, or moving the camera." 

I'm arguing it's different even in two static shots between different formats.  The angle of view might be the same, but the camera's relationship to the angle is not.

 

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Regarding the comments on perspective, in computer graphics, perspective projection in its simplest form is:

s = 1.0;

o = ObjectPoints(i) // the object in this example is a bunch of 3D points

p.x = o.x*s/o.z

p.y = o.y*s/o.z

You can see that if we increase s, the object will appear bigger on screen, and the FOV will get narrower (same as increasing the focal length on a camera) and we'll 'compress' the image (less distortion).

If we move the object closer to the camera (make o.z smaller), we have to reduce s (same as lowering the focal length) if we want the object to be roughly the same size on screen. This increases the FOV and increases perspective distortion because each o.z has a greater effect (in Orthographic projection, we just drop o.z and don't divide at all- zero distortion). If we move away from the camera, we must increase s to keep it about the same size on screen, and this reduces perspective distortion and 'compresses' the image.

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Adding to the post from @jcs:

The FoV (or angle of view for photography/videography) relative to the sensor size and focal length is given by the following equations:

Horizontal FOV = 2 * arctan( SensorWidth / EffectiveFocalLength)

Vertical FOV = 2 * arctan( SensorHeight / EffectiveFocalLength)

Here is what happens when you move the camera relative to an object (Changing the FoV only keeps the transversed magnification constant to make the perspective changes easier to spot) : 

Camera_focal_length_distance_house_animation.gif

 

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47 minutes ago, Viscount Omega said:

 

I'm arguing it's different even in two static shots between different formats.  The angle of view might be the same, but the camera's relationship to the angle is not.

 

Well, sorry, but you're not correct on this. If the camera position is the same on both cases (actually position of the entrance pupil) then perspective will be the same on both cameras. Field of view may differ depending on focal length and sensor size. Maximum field of view will be limited by the image circle size.

Try sitting in a chair and staring straight ahead. Now try to change the perspective of the scene in front of you. You can't do this without moving your position, or moving the position of objects in the scene. Neither can a camera. 

 

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1 hour ago, jcs said:

In summary, what we have been discussing is the notion that any format has any special and unique look or characteristic: 'full frame look' and 'medium format look' really mean a 'shallow depth of field look' or in some cases 'swirly bokeh' or other lens artifacts, which aren't specific to any sensor size or any lenses designed for a specific format.

Yes. Except you miss the point again and again, which is a lens only works for it's intended image circle (and full look) on a certain size format... Thus if you like a lens that is designed for a FF format when used on FF, then it indeed has that "FF look" (as non-descriptive as that is). Your definitions are your definitions, whether you wish people used other terms or not is irrelevant, because they don't and is the reason you are in the perpetual argument now. (It's the same thing as me telling you that "look" is not the right word to describe equivalency, then you telling me that it is ;) .)

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On 3/4/2017 at 1:55 AM, Brian Caldwell said:

Let me get this straight - are you denying that the combination of an 80mm lens with a 0.7x focal reducer is a 56mm lens?

My "no" in the post you quoted was in response a question regarding my concurrence with and understanding of one of your earlier posts.

 

However, I do not think that a 80mm, MF lens with a 0.7x focal reducer would look the same as a FF, 56mm lens.

On 3/4/2017 at 2:36 AM, jcs said:

Haha Kaylee I'm pretty sure @tupp is putting one over on us and is joking at this point.

I am completely serious,  I am willing to conduct a proper DOF/look comparison, but an equivalence supporter has to be present to verify "equivalent" settings.

 

Of course, a view camera, lens and some sort of large digital back would have to be procured, as would a S16 camera and S16 lens.

 

On 3/4/2017 at 2:36 AM, jcs said:

If you're still not convinced that it's not sensor size but rather optics that matter with respect to a certain look,

You don't seem to be understanding the point (in spite of the fact that it has been repeated several times in this forum).  Again, it is not the sensor size -- it's the optics designed around a sensor size.

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2 hours ago, jcs said:

'full frame look' and 'medium format look' really mean a 'shallow depth of field look' or in some cases 'swirly bokeh' or other lens artifacts, which aren't specific to any sensor size or any lenses designed for a specific format.

Oh, hell no.  I think depth of field and sensors are irrelevant.  I don't deny lens artifacts may contribute to a certain "look" but I don't think they are the "main thing".  The problem, I think, is trying to quantify a subtle difference in perspective between 2 formats.  Hence, you have people constantly using vague words like "look" and "feel".

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6 hours ago, Mattias Burling said:

Imo, it murdered anything digital I ever saw. Much much better quality.

And this is the point of everything. We have different tastes and put different aspects on top of the list when we say "image quality".
Some are all about mp others DR, etc.

It looked great, don't misunderstand me. I loved the experience.

Compared to the resolution and imaging in say Revenant, however, it wasn't as solid and crisp. --which is fine. 

I mean, H8 WAS an honest to goodness "film." That nice organic soft roll off look.  Really good watching film in its traditional glory, but for me I kept thinking, "this is wonderful, yet digital projection is more solid."

Then again, I watched Jaws again last week and loved the digital transmission of the (restored?) film.

Best case scenario: shot on film, scanned, edited, projected digitally?

One thing that a lot of young folks (probably not you) tend to forget, or are maybe unaware of, is that film projection had diminishing quality the longer it was on the circuit... 

My childhood is full of watching flicks at the local $1 mantinee grindhouse.  Y'all can't appreciate how crazy beat up those prints would be by the time they hit the theatre I could afford to go to.

Then, while on my first career gig in Mississippi, I used to literally go to a converted cotton gin to watch films. It was glorious and lousy all at the same time. 

The projectionist was this sweet cinefile with asperger's who never really knew how to run the projector. 

Gate problems, bad focus, missing reels, the whole bit.  Romantic and fun in a nostalgic way, but never all that "pristine."

Film is beautiful, but it's certainly not visually practical compared to digital.  And when both are more or less equal, we'll...

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On 3/4/2017 at 0:35 PM, hyalinejim said:

@tupp all those small differences in your AB comparison are of course accounted for by the things that you mention, entrance pupil distance, diffraction, etc. etc.

The differences are not small, and the A/B comparison mostly discussed in this thread was not "mine."  I merely presented that comparison in a format that made more conspicuous the DOF differences that some of us can see just by looking at two photos side-by-side.  I think that I circled six different areas that showed palpable focus differences.

 

There were two other comparisons in which the differences were much more dramatic.  Of course, those two damning comparisons have been downplayed.

 

On 3/4/2017 at 0:35 PM, hyalinejim said:

These factors don't enter into equivalence calculations, nor do they contradict them.

I thought that I had already made this point earlier in this thread.

 

On 3/4/2017 at 0:35 PM, hyalinejim said:

Their effect is so minimal as to be altogether invisible to the average viewer, despite their dramatic apparence to you. Relative to the changes in image wrought by changing focal length, aperture, or sensor size, their effect is negligible.

No.  Here is another equivalence "proof" linked early in this thread.  It compares the DOF of an Iphone camera with that of an APS-C DSLR.  Look at the two photos, with the "Jack Black" bottle perfectly sharp in both photos.  Note the bush and car in the background to the left of the bottle.  Guess which image was shot on a small Iphone camera.

 

Do you really think that the average viewer wouldn't notice the huge difference in DOF at the bush/car?  When you "click-to-enlarge" these images, the DOF difference becomes even more obvious.

 

DOF differences become a lot less "negligible" when the tester actually uses dramatically different formats with actually different lenses (the Brightland Studios comparisons actually used the same zoom lens for every image).

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1 hour ago, tupp said:

You don't seem to be understanding the point (in spite of the fact that it has been repeated several times in this forum).  Again, it is not the sensor size -- it's the optics designed around a sensor size.

 

@tupp I know you say you're serious however I've been saying it's the optics, and only the optics for this entire thread (this a quote of what I wrote from your post quoting me):

Quote

If you're still not convinced that it's not sensor size but rather optics that matter with respect to a certain look,

Are you even reading my posts lol?

So now we're in agreement that it's not sensor size, great!

Let's get on with debunking lenses designed for a certain sensor size format have special properties not present in lenses designed for other formats. You're going to need a large format camera vs. Super 16 in order to demonstrate the effect your propose is real? Why not use a cellphone vs. the World's Largest Camera? Yes I'm joking, to demonstrate the absurdity of all this :)

There are no significant looks or special properties for lenses designed for a specific format either. With the lens somewhat close to the subject I suppose size could matter, however there are full frame lenses bigger than medium format lenses so that's not it. What is it about medium format lenses (or large format lenses) that make them produce a unique look only available to those lenses? Can you show us examples demonstrating these unique qualities? That also means strapping a focal reducer to a medium format lens captures these special properties and makes them available to a full frame sensor? Any examples to share? (swirly bokeh as shown in this thread is also available with full frame lenses).

1 hour ago, tweak said:

Yes. Except you miss the point again and again, which is a lens only works for it's intended image circle (and full look) on a certain size format... Thus if you like a lens that is designed for a FF format when used on FF, then it indeed has that "FF look" (as non-descriptive as that is). Your definitions are your definitions, whether you wish people used other terms or not is irrelevant, because they don't and is the reason you are in the perpetual argument now. (It's the same thing as me telling you that "look" is not the right word to describe equivalency, then you telling me that it is ;) .)

As with the sub-debate with @tupp, I've been saying it's the optics, and only the optics, for this entire thread. The debate was sensor size having an effect, or not.

Now the debate has moved to lenses designed for a specific format have some kind of unique properties only available to those lenses. What are these special properties, and where is the proof supporting this claim?

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4 hours ago, jcs said:

@tupp I know you say you're serious however I've been saying it's the optics, and only the optics for this entire thread (this a quote of what I wrote from your post quoting me):

I know you have been saying that -- you have been repeating that point as if those of us who have a differing view think that the look/DOF is only dependent on that actual sensor/film size.

 

By the way, if one crops too severely into the image circle, the look and "sharpness" does change.

 

4 hours ago, jcs said:

Let's get on with debunking lenses designed for a certain sensor size format have special properties not present in lenses designed for other formats.

Ha!  Well, let's get on with resolving the issue in regards to optics generally having different looks/DOF for different when designed for different sized formats.

 

 

4 hours ago, jcs said:

You're going to need a large format camera vs. Super 16 in order to demonstrate the effect your propose is real? Why not use a cellphone vs. the World's Largest Camera? Yes I'm joking, to demonstrate the absurdity of all this

No.  You and others have unwittingly demonstrated that there generally is a difference in look/DOF between lenses designed for different formats -- you just won't accept your own results.

 

So, we need to go to extremes to show a difference that is undeniable.

 

Although every equivalence test that I have seen so far has fundamental flaws,  the photographylive.com equivalence comparison seems to employ the most diverse extremes in formats to date -- it compares a cellphone camera to an APS-C DSLR.  As predicted, such two extremes exhibit a conspicuous discrepancy in DOF and look, so much so, that one has to wonder if the tester who concluded "equivalence" is legally blind.

 

I think you will find that the bigger the difference in the size of the lenses' image circles, the bigger the discrepancy in their DOF roll-off and look.

 

4 hours ago, jcs said:

There are no significant looks or special properties for lenses designed for a specific format either.

The results of your tests and others indicate the opposite.

 

 

4 hours ago, jcs said:

With the lens somewhat close to the subject I suppose size could matter, however there are full frame lenses bigger than medium format lenses so that's not it. What is it about medium format lenses (or large format lenses) that make them produce a unique look only available to those lenses?

You seem to have made the assumption that the physical size of the optics are the primary/sole variable that I think is causing a difference in look.  Such an assumption is incorrect.

 

If anything, it is the ratio of the size of the optics relative to the focal length, or the size of the optics relative to the image circle.  Note that lenses made for smaller formats generally have larger such ratios when compared to lenses designed for larger formats (especially view camera lenses, which necessarily have expansive image circles to accommodate substantial swings, tilts and shifts).

 

So, the smaller format optics are generally larger relative to their focal lengths and image circles.

 

I have given a list of other possible focus/look variables earlier in this thread.

 

 

4 hours ago, jcs said:

Can you show us examples demonstrating these unique qualities?

Yes.  Take an honest look at your own, flawed equivalence tests and at those tests of others.

 

 

4 hours ago, jcs said:

That also means strapping a focal reducer to a medium format lens captures these special properties and makes them available to a full frame sensor?

Yes... assuming that condensing stage is perfect.

 

 

4 hours ago, jcs said:

Any examples to share? (swirly bokeh as shown in this thread is also available with full frame lenses).

I have seen some nice images from the OP of this thread, but I have not yet seen an "equivalency" test with the Kipon MF focal reducer.

 

Swirly bokey is available with S16 lenses -- swirly bokeh is not indicative of a larger/smaller format look.

 

 

6 hours ago, hyalinejim said:

If the camera position is the same on both cases (actually position of the entrance pupil) then perspective will be the same on both cameras.

Actually, this statement is not entirely true.  Shifting, tilting and swinging can certainly change the perspective in camera (and in a projector/enlarger).

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@tupp the equivalence equations and test images don't claim to be pixel perfect, only a tool to set up cameras and lenses as equivalent as possible. You've looked at them all and proclaimed, "ha HA! The two images aren't perfect so it's invalid!", right? Then when shown pixel perfect computer simulations (which can in fact model any defect/transfer functions you'd like) you proclaimed, "simulations aren't reality so it's invalid!". I was providing information I thought would be helpful. If it doesn't work for you, no worries.

If anyone can show that any specific lens has special properties only available for the format the lens was designed for, I look forward to seeing the results.

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16 minutes ago, jcs said:

@tupp the equivalence equations and test images don't claim to be pixel perfect, only a tool to set up cameras and lenses as equivalent as possible. You've looked at them all and proclaimed, "ha HA! The two images aren't perfect so it's invalid!", right?

No.  Those test images are FAR from equivalent.  Furthermore, your second comparison (the one with the focus processing variable eliminated) exhibits huge, conspicuous DOF discrepancies, in spite of the lack of any middle ground to reveal how the DOF rolls off.

 

Likewise, the photograhylife.com equivalence test has no revealing middle ground, but it employed more diverse extremes of format sizes, and, consequently, it shows even more obvious DOF discrepancies.

 

Face the results your own tests and of the tests of others.

 

 

16 minutes ago, jcs said:

Then when shown pixel perfect computer simulations (which can in fact model any defect/transfer functions you'd like) you proclaimed, "simulations aren't reality so it's invalid!".

Yes, because it is true -- simulations are not reality.

 

In addition, the linked simulation that you mention did not factor-in several important variables (as I have suggested earlier in this thread), thus the simulation is worthless.

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