jcs

Are you joking? Multiplying the aperture by the crop factor is mathematically required if one wishes to shoot with equivalence between two camera systems (for example, shooting a GH4 and 5D3 and desiring to get the same basic FOV and DOF for both cameras). Did you try the DOF/POV simulator? http://dofsimulator.net/en/ . Of course you can also try setting up two different sensor size camera systems and try to match FOV and DOF. If you do, you'll find that you need to multiply the aperture by the crop factor (and the ISO by the square of the crop factor if desiring to also match exposure). Perhaps you could post an example with your cameras where you match DOF and FOV along with focal length, aperture, and ISO for both cameras? (you can skip the math and do it by eye, the results may surprise you)

Winning arguments is a waste of time unless prosecuting a lawsuit. Learning new things and helping others is time better spent.
MF vs. FF can be tested with the same camera and lens (changing lens settings and post cropping), which will typically show that the sensor size isn't where any effect is coming from. Now the point shifts to lenses- cool, that could be helpful to understand for those thinking about getting an MF body to take advantage of lenses. However Brian Caldwell stated that the current top 35mm lenses are as good or better than MF lenses. Posting equivalence-matched MF-cameras+lenses to FF could be helpful in showing the strengths of the MF lenses vs. FF lenses. Even more useful would be showing the MF lenses can more cost effectively produce images than very expensive FF lenses (Otus etc.). This same argument is valid when comparing FF to m43: FF lenses are effectively cheaper to get super shallow DOF.

Winning arguments is a waste of time unless prosecuting a lawsuit. Learning new things and helping others is time better spent.
MF vs. FF can be tested with the same camera and lens (changing lens settings and post cropping), which will typically show that the sensor size isn't where any effect is coming from. Now the point shifts to lenses- cool, that could be helpful to understand for those thinking about getting an MF body to take advantage of lenses. However Brian Caldwell stated that the current top 35mm lenses are as good or better than MF lenses. Posting equivalence-matched MF-cameras+lenses to FF could be helpful in showing the strengths of the MF lenses vs. FF lenses. Even more useful would be showing the MF lenses can more cost effectively produce images than very expensive FF lenses (Otus etc.). This same argument is valid when comparing FF to m43: FF lenses are effectively cheaper to get super shallow DOF.

I just hope it doesn't run into this type of situation. Three FF cameras to scale: notice the mirrorless one has an enormous flange. I think it's just physics.

Petapixel had a whole article on this here:
http://petapixel.com/2016/04/04/sonys-full-frame-pro-mirrorless-fatal-mistake/

"DOF falloff"  seems like a really poor term.  How about simply "defocus", or perhaps "MTF as a function of defocus" - which I think is what people actually mean.  In optics this is referred to as "through-focus MTF", and its a standard and useful way to characterize a design.  It will vary from design to design because it is strongly aberration dependent, but it has nothing to do with sensor size.
One advantage that larger formats have is that you can use a smaller relative aperture to achieve a given DOF.  Since aberration correction tends to be very non-linear with respect to f/# you often wind up with better correction on a larger format.  For instance, I used to shoot 11x14" film a fair amount, and aside from an advantage in film grain it allowed me to shoot at f/16 instead of the ~f/1.4 I would have had to use on 24x36 format to achieve an equivalent picture.  Focal lengths scaled accordingly, naturally.  At f/16 the ultra large format lens was nearly diffraction-limited, whereas a small format lens at f/1.4 is nowhere near that limit.  Of course, as you depart from such extremes in aperture any potential optical differences between large and small formats begin to disappear, and these differences are further minimized by improved sensor quality.  So that ridiculously huge view camera stays on the shelf these days!
Regarding the argument about whether a long lens on a large format has less perspective distortion than a proportionally scaled lens on a smaller format, the answer is "no".  In terms of perspective and geometry, all lenses mimic the behavior of simple pinhole cameras - with the possible exception of rectilinear distortion which is generally a non-issue.  One other thing to be aware of is that larger formats require a larger magnification, which essentially means you are using a longer lens than you may think you are for close-ups.  For example, when shooting close portraits on 11x14" I was typically shooting at around -1x magnification, which effectively doubles the length of the lens.  However, when you take this effect into account any potential discrepancies go away, and you are left with the stark reality that larger formats really don't offer any special "magic".

Perhaps I could call such a product "The Naked Emperor Focal Reducer"?  At least then I could sleep at night.  I thought Kipon announced one of these, but it still seems to be vaporware.
To be clear, adding a focal reducer to a medium format lens to convert it to a 24x36 format lens will only result in a slowish FF lens.  That's because medium format lenses tend to have very conservative designs and are very slow to begin with.  I can't think of a single MF lens + focal reducer combination that would be a compelling new addition to the FF optical repertoire.  As you have correctly implied, there is no magic to be found here.
 

I took the Full Frame Look (vs. S35) challenge and created images that were equivalent: http://brightland.com/w/the-full-frame-look-is-a-myth-heres-how-to-prove-it-for-yourself/ . Some folks posted 'debunking' shots with MF vs. FF but didn't use equivalent camera settings per the math (and not even the same framing).
The math and physics also apply to MF vs FF. If it's possible to match via the equivalence equations an MF camera + lens to a FF camera + lens, the images will be identical. However, part of the difference is the sensor technology and software processing, where Phase One appears to really shine. Thus comparing a Canon 1DX II or Nikon D5 to a Phase One (any recent) may still show the Phase One providing a better image. If that wasn't the case, there wouldn't be a market for these very expensive MF cameras.

JCS, 
Keep up the good work.  Much appreciated that you share your videos and expertise too.  Cheers.

Viewfinder is helpful outside in bright light, handheld shots are more stable (3 point contact when using viewfinder + handle + mass), Canon Log 2 highlight roll off (much better than even CLog on the 1DC), and most importantly, when using the 'ARRI' config, post grading is super fast and skintones look great with little effort. While this episode was shot in 4K, when 1080p is desired (for faster edits and smaller files), the C300 II's 1080p is much better than the 1DX II's (soft, aliased). For stills, stealth video, and 4K60, the 1DX II is superior.

Thanks for sharing jcs, that was fun.

Those are indeed visible differences for as 'ideal' a test as is physically possible since a very high quality zoom lens was used on the same camera (cropping in post after changing settings to simulate an APS-C crop). Since the differences are very subtle, the aesthetic quality boost may be lost on the general public, in the same way as fine food and alcohol, can be etc. Were the Hateful 8 and The Revenant better movies being shot on the ARRI 65? Did they make more money because of the large format camera used? (smaller format cameras were also used). The answers to both questions is probably not significantly. With effectively unlimited budgets, why not shoot on the 'best'? The relative cost of the larger format camera is insignificant to the film's budget. However using the pinnacle-best gear makes the directors and DPs happy, and that counts for something.
Using the DOF simulator, I noticed the circle of confusion and other parameters weren't exactly the same between formats. While FOV and DOF will be nearly identical, subtle things as noted such as blur transition region stretching can be analyzed by tracing individual light rays- photons. My crop test was not perfect, however there is a way to study this without worrying about issues of optics or lenses: computer simulation via ray tracing. This could be used to create graphs showing the increase in blur transition regions based on the sensor size. If it's a real effect, the results could be presented to optical designers such as Caldwell to show a possible market for a MF to FF focal reducer. If not by Caldwell, perhaps someone else in HK or CN.
Someone with the desire and free time could explore ray tracing to create renders showing any advantages to larger sensor sizes using Blender (free): https://www.blender.org/features/cycles/ . Since this is a controversial subject, showing these kinds of results could help visually explain effects previously difficult to put into words. I need to get back to working on improving content and storytelling- more important than tech!
 
 

point of focus is the text on the front of the lens.  bokeh bubbles are the same for both shots meaning the ratio between the in focus and fully out of focus areas is the same.  HOWEVER, on the aps-c shot the canon text on the camera body, the underside of the tripod head, and the text on the flash are are more blurred than the full frame image.  
so for a bigger sensor the dof rolloff is slower and therefore more of the camera is in focus.  as distance increases and focal length is lengthened this attribute is magnified.
 

I took the Full Frame Look (vs. S35) challenge and created images that were equivalent: http://brightland.com/w/the-full-frame-look-is-a-myth-heres-how-to-prove-it-for-yourself/ . Some folks posted 'debunking' shots with MF vs. FF but didn't use equivalent camera settings per the math (and not even the same framing).
The math and physics also apply to MF vs FF. If it's possible to match via the equivalence equations an MF camera + lens to a FF camera + lens, the images will be identical. However, part of the difference is the sensor technology and software processing, where Phase One appears to really shine. Thus comparing a Canon 1DX II or Nikon D5 to a Phase One (any recent) may still show the Phase One providing a better image. If that wasn't the case, there wouldn't be a market for these very expensive MF cameras.

Sure, but it's a technical medium. Nerds are needed. That's why cinema is such an inclusive craft/art form.  Making movies needs a big tent. The technical and artistic. 

Winning arguments is a waste of time unless prosecuting a lawsuit. Learning new things and helping others is time better spent.
MF vs. FF can be tested with the same camera and lens (changing lens settings and post cropping), which will typically show that the sensor size isn't where any effect is coming from. Now the point shifts to lenses- cool, that could be helpful to understand for those thinking about getting an MF body to take advantage of lenses. However Brian Caldwell stated that the current top 35mm lenses are as good or better than MF lenses. Posting equivalence-matched MF-cameras+lenses to FF could be helpful in showing the strengths of the MF lenses vs. FF lenses. Even more useful would be showing the MF lenses can more cost effectively produce images than very expensive FF lenses (Otus etc.). This same argument is valid when comparing FF to m43: FF lenses are effectively cheaper to get super shallow DOF.

If no one is willing to do some work and actually do a test comparing MF to FF in the real world with equivalent settings, then what's the point of debating without any comparative evidence? I'm a cognitive scientist, open-minded and willing to learn new things. That said, a valid scientific test, which is easy to do is all that's needed to make a useful point regarding MF vs. FF.
If the only difference is MF lens design, that's cool, however this debate was MF vs. FF cameras (and again, Caldwell says no advantage for MF lenses anymore; no point in a MF => FF SpeedBooster).
If an MF camera system (body + lens) is truly better than FF, I'd invest in MF. So far there's no comparative evidence showing this to be true (the only scientifically valid way to determine if there's a difference).

Here's the math- where's the error? http://www.josephjamesphotography.com/equivalence/
I replicated with actual test and images, and got the results predicted by the math ( http://brightland.com/w/the-full-frame-look-is-a-myth-heres-how-to-prove-it-for-yourself/ ).
If Phase One or Hasselblad sent me a camera and lenses, I'd be happy to shoot equivalence tests against the Canon 1DX II and L-lenses and post the results.

Viewfinder is helpful outside in bright light, handheld shots are more stable (3 point contact when using viewfinder + handle + mass), Canon Log 2 highlight roll off (much better than even CLog on the 1DC), and most importantly, when using the 'ARRI' config, post grading is super fast and skintones look great with little effort. While this episode was shot in 4K, when 1080p is desired (for faster edits and smaller files), the C300 II's 1080p is much better than the 1DX II's (soft, aliased). For stills, stealth video, and 4K60, the 1DX II is superior.

Now that's what the Magic Lantern team should do. Hack the APS-H M8 or the FF M9 CCD cameras and give them video with Leica/Kodak/DB Mojo I would pay anything
I'm very pleased with the colors straight from my M8s sensor.

I know it won't happen and is probably impossible, but still....

Perhaps.  But then again, I say as a documentarian, so what?  From the POV of my reality I think I disagree with your assertion.
I guess, by certain perception, I'm in the "I can barely make it" camp.  As it happens, I've never been beholden to the idea that certain gear is inherently not-good-enough simply because of the market it's being sold to.  I rent when I need to and I shoot with many of these contemptible "toys" when I need to.  My opinion is that a tool is a tool.  I'm not going to bring a "knife to a gun fight" nor am I going to do the opposite.
It's curious, I think, how some people perceive themselves as superior in an (supposedly) artistic medium simply because they have more expensive pro tools to do the craft.  Does anyone else find that odd?  Especially these days?  That sort of elitism was curious even a decade ago.  Now, it really doesn't make sense.  Anyone with $3K can access more than good enough IQ/audio/post for a production that, with skill, will look around 90%+ as good as anything.  That's NOT rhetoric.  I'm convinced it's just the truth. 
What am I to believe?  The defensive opinions of industry professionals threatened by the gear democratization, or my lying eyes when I see the work of Kendy Ty or a Ruslan Pelykh?  You tell me, because there are a lot of people out there kicking ass with cameras that wouldn't even cover the cost of a friggin' camera battery from a few decades ago.
What get delivered is what counts.*
But, as far as I'm concerned, if I artistically need to use an iPhone or an Alexa to cross a finish line, that's what's gonna happen.  And for what I'm doing, it's been leaning toward the former rather than the later for years now.
Finally, I'd even argue "amateurs" is exactly a pejorative.  If anything, by the original etymology of that word, it probably has more merit and artistic integrity these days than "professional."
* ( For reasons only they can justify, a lot of corporate work I do actually wants the allure of "real" gear around during the process. )

I've just finished filming a short film.  We used 5D Raw, A7s + speed booster, GH4 + speed booster, and the XC10.  The best looking and "organic moving" footage in my opinion came from the 5D Raw and the xc10 in 4k.  The a7s was the 3rd best and the gh4 was the sharpest "out of camera".  We could have comfortably shot the whole thing on the XC10.  

Unsharpened ungraded CLOG frame grabs. Having a 1 inch sensor is no hindrance for a shooter like me...i own multiple cameras and i light my shoots.  I'm invested in canon gear, it uses the same batteries as the 5D3, has good battery run time, doesn't overheat and captures excellent video quality that compliments 5D Raw. I don't have to carry around a 25lb camera bag with various lenses and accessories to be able to shoot dynamically with the xc10.  The only accessory I carry is a variable nd filter.  I like to minize rigging as much as possible and I don't want an xlr input on this form factor, a rode videomic pro is good enough.  The only thing i would like is a constant f/2.8 and true DPAF.  I wouldn't even bother with a C100-300 if it had those 2 features.  




More ungraded frames of CLOG + Variable ND filter of me testing the cam on a poor trapped dog.  

Such as 79,400 views for that camera test. Northrup and Dugdale have millions of views by making camera tests entertaining. Whether you agree with them or not, they are creating content that many people enjoy watching. My 'best' camera test only got 26K views- no story and pretty boring (this kindof had a story, though not much really going on (11.5K views)). How about yours?

Excellent shots, especially the extreme close ups!

Over the Memorial Day weekend we decided to pop over the San Francisco. I figured it would be a good opportunity to have a little fun with the 1DX MkII. We are still getting use to the camera but so far really like it. The batteries last a long time. I would generally get between 1-2 days out of each. I was also testing out a Zacuto Marauda... It helps but I definitely need practice to master it. I might end up returning the Zacuto and going with the Rhino Rig, which I expect to have in hand next week. I think the Rhino Rig should be more stable and can break down pretty small also. FYI: I also had a chance to stop by Sammys Camera and check out the Canon 11-24mm... It's an impressive piece of glass. I will have some test shots with that bad boy later on. I forget the exact settings, but I know in a few of the shots I was pushing the ISO in excess of 8,000 and it seemed to hold up pretty well. I know that some of you dislike the new color profile, but I personally love it. I did load some flat picture styles onto the camera, but don't think I used them in these clips. Sorry for the clipping of the audio, I just wanted to throw this up so you could all see what it looks like in the hands of a non-pro.
Canon_1DX_MkII_-_San_Francisco.mov

Hello all,

I was fortunate to get my hands on a 1dx mark II a few weeks ago, along with an underwater housing for it.  Did a last minute trip to the Philippines to test this out.

It is a short video, and I did a mix of macro and wide angle.  I used the 100mm F2.8L and some shots with a +10 diopter on it.  For wide angle I used the 16-35mm F4L.  Make sure to choose 4k on the playback options.
I severely underestimated what the move to 4k was going to bring.  The amount of resources both from a speed and storage standpoint is massive.  After 40 dives, I came back with about 3.5TB worth of data.  Almost all of these shots were shot 4k and 60p, played back at 30p.

Let me know what you think!
Enjoy,

Dustin
 
Or Vimeo