tupp

9 hours ago, TheRenaissanceMan said:

Or if you're looking for something even studier, you could go for a used Matthews beefy baby.

A combo stand is much sturdier than a baby stand.  Essentially, a combo stand is a junior stand that includes a smaller, pop-up baby pin.

 

 

6 hours ago, IronFilm said:

Ordering from B&H isn't really an option for these extremely heavy items when you live overseas :-/

I think Kupo is based in Korea, but I am fairly sure that they have worldwide dealers.  Their starting list price seems very competitive.

 

 

5 hours ago, Kisaha said:

but some were definitely Arri and other well know brands,

Not sure if Arri is considered a "well known brand" in regards to grip equipment.  I have never seen an Arri combo stand on set.

Never tried those stands, but Kupo is a decent, established brand from Asia, and they have pretty good prices on their combo stands.

Loosen the lowermost knob (where the light's stand fitting meets the light stand) and pan, then re-tighten that knob.

 

Or, loosen one of the stand's stem knobs WHILE FIRMLY HOLDING THE STEM ABOVE THAT KNOB.  Then, re-tighten that knob.

This is great news!

 

It appears that they have picked a better default sensor than their original choice (CMOSIS 12000), which was the same sensor in BM's 4k cameras.  I would guess that this Kodak sensor avoids the FPN problems inherent in the CMOSIS sensor.

 

 

1 hour ago, zerocool22 said:

I think they just came a bit late to the show.

Apertus has been making raw, open source cameras for around a decade.

 

 

1 hour ago, zerocool22 said:

Hope it gets swappable sensors as well

If anyone can do it, the Apertus people can.  However, I don't think that it can work that simply -- there has to be electronics/processing specific to each sensor.  So, at minimum, it would be a swappable sensor/electronics module (which would essentially be the entire camera, minus the recorder).

 

 

1 hour ago, zerocool22 said:

But I will probably stick with a ursa mini pro.

Too bad the BM ASP-C/Super35 cameras lack an MFT mount.  The MFT mount on the ASP-C Axiom makes it very versatile.

There are several companies who make fabric egg crates.  Some fabric egg crates include "pop-out" frames.  Light-Tools will probably be the most expensive brand.  Don't know if anyone will have your exact size (120x100cm) "off-the-shelf," but the manufacturer in the link (The Rag Place) can make custom sizes.

 

Years ago, grip manufacturers offered black, aluminum, honeycomb grid sheets, but I haven't seen those in awhile.

2 hours ago, jcs said:

The most powerful on the market appears to be this guy: http://aadyntech.com/products/the-punch-plus/, at 64,090 lux at 10 feet!

The Nila Arina appears to be one stop brighter, and it is doubtful that the Arina has the highest output of all LED filmmaking lights.  Nila was one of the very first high-power LED brands, so they have years of experience in designing for the film industry.

 

1 hour ago, andy lee said:

Are they weather sealed like HMI lights as I'm looking for LED lights to replace Arri M18s smaller lighter as powerful and weather sealed for out door use for a job

There are weatherproof versions of the Nila fixtures.  I would also check out Mole and other major brands.

11 hours ago, Mattias Burling said:

suck my balls

We'll probably need a macro lens for that. 

Possible straggler.

1 hour ago, andrew berekdar said:

Just a note in addition to the issues raised by others above - If you are going to use an open face tungsten lamp, be aware that if the bulb blows and the lamp is pointed at your interviewee you could have a very serious situation on your hands

Manufacturers in the USA have been putting protective screens over the front of their open-face halogen fixtures since the early 1990s.  This practice was mandated by a few local fire depts. (mostly SoCal) in their push for testing lab approval (ETL, UL, etc.) for filmmaking fixtures.  These protective screens are basically scrims that block 25%-or-less of the light.  To avoid liability, some lighting manufacturers (the smart ones) provide these protective screens for free, even if one has a used, out-of-warranty fixture.

 

Always use a protective screen (or some other barrier) in front of an open face halogen source.

 

In regards to the lighting needed for OP's shoot, OP needs to first determine what the client means by "hard light" (as  @TheRenaissanceMan suggested in an earlier post.  A lot of folks confuse "spot lighting" with "hard" light, and those two lighting conditions are not necessarily the same.  (In fact, the "spot" setting on most focusable fixtures is actually softer than the "flood" setting.)  Also, many confuse "contrasty" lighting with "hard" lighting.

 

It would probably best to get the client to link an example of what he/she wants.

If you frequently will be shooting outdoors, you might consider using rags that breathe, as ripstop nylon and sail cloth can turn your "6-by" (2mx2m frame) into a powerful sail/kite.  When I used to build frames out of PVC, I would mostly use cheap, white bed sheets as a silk.

 

Also, it might be good to use "grommets and ties" to attach the rags to the frame, as they are secure and easy to use, and they can be readily adapted to fly the rags in other ways, without the frame.

You might consider something like the Lowel Tota-Tilter:

 

There is no locking mechanism for the tilt -- it just provides constant tension.  The pan would require loosening the black knob.  You would also need a stud/baby-pin to mount it.

Perhaps a flex-arm solution could work.  Such a set-up would allow you to hold the camera in one hand and adjust the monitor with the other hand.

 

Here's the Manfrotto flex-arm:

 

 

Here is some other gooseneck for a tablet:

 

 

Here is the Lowel Flexi-Shaft (modular system):

 

 

Here is a Matthews flex-arm:

 

Here is some audio gooseneck selling at B&H:

8 hours ago, Brian Caldwell said:

Well, the combination of an 80mm lens and a 0.7x focal reducer does have a focal length of 56mm.  After all, focal reducers really do reduce focal length.

I do not dispute this assertion.

 

 

8 hours ago, Brian Caldwell said:

And if you use that 56mm lens on FF (24x36mm) format, then *it is* a FF 56mm lens.

Right -- it becomes a 56mm FF lens, with the properties of an 80mm lens on MF.

 

 

8 hours ago, Brian Caldwell said:

In this case, the use of a focal reducer together with an 80mm lens is a perfectly valid way of designing and creating a true 56mm lens.

Well, adding a condensing stage as part of a unified lens design merely to achieve a certain focal length (no boost in brightness nor look needed) might seem like a roundabout and expensive way to achieve that focal length.

 

Why not just design a simpler lens with the desired focal length -- without any focal reduction stage?

 

 

8 hours ago, Brian Caldwell said:

As I mentioned in my earlier post, the only possible reason it will look different from any other 56mm lens will be due to lens/reducer aberrations and other flaws.

LMFTFY:  The only reason that it will look different from any other lens will be due to lens/reducer aberrations and other variables.

 

 

7 hours ago, cantsin said:

Since we have the great privilege of having Brian Caldwell, the designer of the Metabones Speed Booster, here on this forum - can we rest the discussion with his above statement? 

No.  The subject of equivalence will not be resolved until a proper test is conducted.

15 hours ago, bunk said:

You either have a bad memory or you didn't read the thread

Or, perhaps you are making an incorrect assumption about why I referenced that simulation and about who I was addressing.

 

 

15 hours ago, bunk said:

The simulation wasn't created for you. Matthias denied what Timotheus wrote...

Not sure of the relevance of the fact that the simulation was not created for me nor of the relevance of Mattias' denial of Timotheus' writing.

 

I was merely responding to another poster who presented that simulation as evidence/proof of the equivalence principle.  Maybe you didn't read (that part of) the thread.

 

 

15 hours ago, bunk said:

No you cant. Look at the Tony Northup frame I posted. It clearly proves that you can replicate the image from a large sensor in the way YOU earlier suggested

Just guessing, but did Mr. "Northup" make yet another equivalence test with a foreground and distant background... but with no middle ground?

 

 

9 hours ago, Viscount Omega said:

But what are your comments on the following theory?

Are you asking me?

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.

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).

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).

On 3/4/2017 at 11:48 AM, fuzzynormal said:

Director: "Hey, we need shallower DOF on this shot, go to a f2.8"

DP "Got it."

The DP's response would most likely be:  "Perhaps it would be better if you shot this yourself..."

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.

4 hours ago, jcs said:

Do you realize that what you are saying is that the lenses are alive and sentient and direct photons differently based on the physical sensor size?

Huh?  How did you read that into my posts?

 

 

4 hours ago, jcs said:

Everything that Mattias posted here is a collective hallucination and focal reducers don't actually work? Or are you just messing with us for kicks? If not, I look forward to your equations and examples showing your concepts in action.

You're going to have to explain how you came to this notion.

 

Again, as the variables are complex, I wouldn't begin to know how to include them in an equation.  Suffice it to say, look/DOF involves more than just f-stop and focal length.

 

I don't see any reason to provide any further examples than the ones that have already been submitted.  If I were to coordinate an equivalence/look test, it would have to compare a tiny format (S16 or 2/3") with a large format (4"x5" or larger), and you would have to be present to ensure properly equivalent combinations of f-stops and focal lengths. 

8 hours ago, jcs said:

The simulations showed a perfect match,

Again, simulations are not reality, and, again, did the simulations to which you refer address the variables of diffraction, physical aperture size, focus field flatness, entrance pupil; ratio of element diameter to focal length, ratio of element diameter to image circle, etc.?

 

8 hours ago, jcs said:

hopefully this simple diagram will show why:

Sorry to be critical, but that is a really lousy diagram.  It is an improper analogy to put the camera sensor and projector screen on the same "side."

 

 

8 hours ago, jcs said:

If we take a movie projector and increase the distance from the projector to the screen, the image grows larger and vice versa. Does the image significantly change other than size? This should make it clear that sensor size by itself does not do anything special for the projected or recorded image. Are we in agreement?

No.  We disagree that this analogy makes sense.

 

A projector focuses a flat, two-dimensional slide onto a flat, two-dimensional screen, while a camera generally focuses a three-dimensional scene with depth onto a two-dimensional sensor (or piece of film).  One scenario is flat on both "sides" while the other scenario is not "flat" on both sides -- that "unflat" scenario involves DOF.

 

 

8 hours ago, jcs said:

Now does the size, shape, curvature, and number of lens elements make a difference with respect to DOF, bokeh, and overall image character? Of course, no one has argued that point as these changes occur between lenses designed for the same format, for example the Canon 50mm 1.4 vs the Canon 50mm 1.2. The 1.2 has a much larger lens and of course a larger aperture.

So, you agree that there is more to DOF than the simple DOF formula involving only f-stop and focal length?  If so, the equivalence principle doesn't always apply.

 

8 hours ago, jcs said:

What happens when we set both lenses to F1.4, or F2.0? Is there still something 'magical' about the 1.2 lens with the much larger glass?

Are they different? Sure they are. Is it significant? Does it matter- we're using the same sensor size?

Much more comparisons here between the 1.8, 1.4, and 1.2: https://www.slrlounge.com/canon-50mm-prime/

We haven't changed sensor size, only lenses, and the bokeh and character is quite different, right?

You seem to be making my point for me.  Glass makes a difference in the look/DOF.  Those two images look dramatically different, but they should have been shot with the exact same f-stop.

 

Sensor/film size is irrelevant, except for the fact that the more that one crops into an image circle, the softer the image gets and, thus, the more one loses the character of the lens.

 

You do understand that I have not been saying that format size is imperative -- the difference in look/DOF mostly involves the optics.

 

 

8 hours ago, jcs said:

Want crazy/weird/artistic bokeh on full frame? Here you go ( http://allphotolenses.com/gallery/item/c_7319.html ):

Everyone agrees that lenses make a huge difference and some full frame lenses have bigger optics than some medium format lenses, right?

That image is one of the best test images for DOF that I have see on this forum -- the continuous iron fence clearly shows the DOF and the DOF roll-off.  All DOF/equivalency tests should be done like this image.

 

Yes.  Some full frame lenses have bigger optics than some medium format lenses.  However, such a scenario would probably jibe with the general differences in look/DOF between smaller format and larger format optics.

 

8 hours ago, jcs said:

If you still feel that sensor size affects the final projected/captured image, can you provide supporting math, physics, diagrams, and real-world examples supporting your hypothesis?

No.  Sensor/film size has little to do with the look/DOF (given that one doesn't crop too severely into the image circle).

 

Also, projectors are irrelevant, as the both the slide and screen are two-dimensional, unlike the 3D scene and 2D sensor/film with a camera.

 

I can't provide the math as there are complex variables of which I would have no idea on how to factor in.  I have listed most of the variables that are probably important above in my first comment of this post.

6 hours ago, jcs said:

On 2/27/2017 at 4:56 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.  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 only caveats being related to aberrations and other flaws in the lens and focal reducer.

@tupp does this make sense now?

No.  I already addressed this passage previously in this thread.

3 hours ago, jcs said:

@tupp, while we agree the two images are not exact, it was acknowledged that it was not possible to make the settings exact for equivalence.

In that case, there are no grounds to conclude that optics from small and larger formats can be made to look identical (nor even to conclude that the equivalence principle is valid) -- nobody can provide proof that such a notion is true.

 

 

3 hours ago, jcs said:

 I don't see anything significantly special or magical about the full frame image, and most people cannot even see a difference without a blink test:

I see a significant difference between the optics for small formats and large formats, and I mentioned a difference in the test in questions when they were posted in another thread without the GIF.  Keep in mind that this comparison was made with the  SAME zoom lens without any middle ground on which to show focus peculiarities (I have repeated these two points several times).  The second comparison shows a fairly obvious difference in DOF, as do most other comparisons linked in this forum.

 

Will try to address other points later...

11 hours ago, jcs said:

At least we've finally established that's there's no such thing as a FF, MF or any or size "look".

We have established not such thing.  So far, every equivalence test has demonstrated a difference in DOF and look between different focal lengths -- even when using the same zoom lens.

 

 

11 hours ago, jcs said:

It's about physics and optics,

Absolutely... and those considering the physics of DOF/focus need to take into account additional optics variables, such as:  diffraction; physical aperture size; focus field flatness; entrance pupil; ratio of element diameter to focal length; ratio of element diameter to fimage circle; etc.

 

Have the equivalence tests submitted to this forum addressed these variables?

 

 

11 hours ago, jcs said:

where even in the same format looks are radically different in terms of bokeh, 3D, etc.

Yes, but the look is not inherent in a format as much as the look is generally inherent in the optics made for a format.

 

Of course, there are exceptions to such a generalization.  For instance, a Fujian 35mm will exhibit a very different DOF and focus field and look on APS-C than a typical 35mm prime set at the same f-stop.  However, this fact just demonstrates there are other important variables to DOF/focus than the f-stop and focal length used in a simple DOF calculation.

 

Do you not think that the actual glass might have some bearing on DOF, focus and look?

 

 

11 hours ago, jcs said:

The (highly imperfect) Canon 85mm F1.2L + 5D3 does nice 3D too (probably stopped down a little):

Fast lenses seem to generally have mushy DOF roll-off.  Perhaps this tendency is due to a larger ratio in element diameter to focal length (or to image circle diameter).

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)?

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.