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tupp

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Posts posted by tupp


  1. @BTM_Pix

    Mplayer can play a file on the destination device while the file is being transferred from the camera to the destination device.  So, if the video file is the right container/codec, a simple script would enable slo-mo playback with mplayer, by starting a transfer and then starting the mplayer playback at the specified frame rate.  This method should work with both USB and wifi file transfers.

     

    Looking forward to hearing your solution!


  2. 3 hours ago, 18hans said:

    But since the playback should start immediatly after recording, I want to avoid processing the videofile. Then also a slow machine like a raspberry probably wouldn't have enough processing power for slowing down the footage fast enough.

    Getting deeper and deeper into the age of instant gratification...

     

    It probably doesn't require a lot of processing power to simply slow down the frame rate -- it just takes a buffer/storage to hold the faster playback stream from the camera.

     

    Mplayer can play a stream from some video files while the file is being stored/created.  Here is an example of how to play the frames of a video file at a frame rate of 23.97 (regardless of the original frame rate):

    Quote

    mplayer -fps 23.97 your_video_file.mov

     

     

    I think that ffplay (the ffmpeg player) can do the same, but I am not too familiar with it.


  3. 2 hours ago, UncleBobsPhotography said:

    Smudging grease on your lens will also make the background softer, but this effect isn't covered by the DOP equivalence formula either.

    Yes, but smudging grease on your lens will simultaneously make the focused foreground softer, so doing so doesn't really affect DOF as much as it affects the overall focus.

     

    On the other hand, an APD filter will not make the focused foreground softer while it does make the bokeh/background softer (than what is expected by the DOF formula).  So, there exist variables other than those in the DOF formula that affect DOF.

     

    By the way, never put grease on your lens -- instead, do so on a clear/UV filter.


  4. On 6/2/2018 at 10:18 AM, Alpicat said:

    As for 1800x1030 resolution (without the sd card hack), with 12 bit lossless you can record for a long time if there's not too much contrast or highlights in a frame. 10 bit lossless is continuous

    That's good to know.  Isn't there some bit depth mode of 9-11 bits?  If so, I wonder if that would give a better, continuous image than 10 bit.

     

     

    On 6/2/2018 at 10:18 AM, Alpicat said:

    There's some slow progress being made with the sd card hack, it's now possible to use it without having to run tests (which took around 3 minutes every time the camera was turned on), so it's quick to start up now. However that build only works with certain fast cards, and it's still not safe to use. If you try that build with an unsupported card, I don't know what would happen to it.

    I actually read about this in the ML thread.  I assume that a Sandisk Extreme Pro works without running the tests.

     

    By the way, I was at the Cinegear trade show two days ago, and both Sandisk and Kingston had a booth.  I told both of them that ML folks are starting to overclock cards, significantly increasing the write speeds.  I suggested that they should consider designing cards meant for overclocking.  Neither company had heard of ML nor card overclocking, but they seemed interested.

     

     

    On 6/2/2018 at 10:18 AM, Alpicat said:

    Below is my latest test, this time with people!

    It looks great!  Thanks for all of your tests!  Seeing people in the frame definitely helps.  The dynamic range looks wide, but it seems like there might have been open sky (and/or a white building) behind the camera.

     

     

    On 6/2/2018 at 10:18 AM, Alpicat said:

    I'm using a Sandisk extreme pro 95mb/s 64gb card

    So, you format this card in the camera with an exfat filesystem?  Do you install ML with this 64GB, exfat card to give the card the boot flag, or do you use some other program to do so?

     

    Thanks!


  5. 40 minutes ago, IronFilm said:

    Did a video recently with the guy from White Point at a trade show in New Zealand, and he let slip they've got a focal reducer coming ?

    The speed  booster was also made by White Point.  The combination yielded  nice look.


  6. Saw a few interesting things.  Zeiss has unveiled six of their Supreme Primes.  A new snorkel company has appeared, and the lenses look pretty good for what they are.  Band Pro has one of the White Point rehoused Blad lenses with a speed booster on a camera, and it is pretty.  Schneider is showing their swing lenses with a PL mount, which was new to me.  OSRAM has on display their HMI STUDIO tungsten-balanced HMI bulbs.

     

    Didn't see much new in regards to cameras.


  7. 8 hours ago, no_connection said:

    Softer and size are two different things.

    Nevertheless, it is a fact that the background is softer with the APD filter in every set of the comparisons that I linked, except for the set with the smallest aperture (f5.6).

     

     

    8 hours ago, no_connection said:
    On 5/31/2018 at 8:30 AM, tupp said:

    However, that gradation of the aperture edge is affecting DOF, and the character of that gradation (combined with the mechanical iris) is one of several variables ignored by the equivalency formula.

    You are grasping at straws.

    Really?  Please explain how the equivalency formula accounts for the effects of a gradated aperture.  Additionally, please explain how the formula accounts for the combined effects of a gradated aperture and a variable iris separated by some distance within an optical system.

     

     

    8 hours ago, no_connection said:

    You are looking for a unified theory and are sad when all it does it describe acceleration. You don't need to worry about light speed when all you do is dropping apples. And compare it to other apples.

    Huh?  Is this some sort of physics metaphor involving Einstein and Newton?


  8. 4 hours ago, no_connection said:

    The APD filter will decrease the apparent aperture and "smooth" it out, and increase DoF somewhat while changing it's character. That is why it's there and what it does. Darkening the edge of the lens is the same thing as stopping it down but smoother. In fact you can do exactly that, stop down by a small amount and take multiple exposures decreasing aperture slightly and then combine them for the the same effect.

    If an apodization filter works like an aperture but with a gradated edge,  then I would agree that it decreases the overall apparent aperture (as long as the mechanical iris is larger).

     

    However, that gradation of the aperture edge is affecting DOF, and the character of that gradation (combined with the mechanical iris) is one of several variables ignored by the equivalency formula.

     

     

    4 hours ago, no_connection said:

    Did you have to grab the one shot he managed to screw up. If you look at the wide open and 1.4 shot you see the bokeh being slightly smaller due to the filter which is 100% expected.

    Ha!  If he screwed up the focus/distance, then he did so in every comparison except for the f1.4 set and the f5.6 set.

     

    In every case except for the 5.6 set, the APD bokeh has a softer edge, as is expected.  In addition, the bokeh progressively gets smaller with each lens as it is stopped down, which is also expected.  On the other hand, the background is softer with the APD filter in every set except for the one at f5.6.

     

    So, I am not sure if he screwed up the tests or if such results are peculiar to using a gradated aperture along with a hard-edged aperture.

     

     

    4 hours ago, no_connection said:

    You could put it at front element and at aperture blades. Front element would not work as well if you use it for FF but probably decent enough for 1.5 or 2x crop. The problem would be finding a filter to begin with.

    It sounds like such a filter would easy to make/airbrush.  It's essentially a radial gradation filter.  It could also just be an opaque disk with a large center hole, with progressively smaller holes radiating outward.


  9.  

    23 hours ago, Deadcode said:
    On 5/29/2018 at 11:24 PM, tupp said:

    The equivalency formula does not take into account all of the variables that affect focus and DOF, therefore it is not absolute.

    I still dont understand what you want to prove. 

    Well, I have demonstrated that the equivalency principle doesn't take into account all of the variables that affect DOF and focus, therefore it is not absolute. ?

     

     

    23 hours ago, Deadcode said:

    Same lens with focal reducer on smaller sensor will give the same look. 

    Yep.  I acknowledged that very point above.  However, that point is irrelevant to the DOF equivalence discussion, and the validity of equivalence is the primary gist of OP's article from which this entire thread follows

     

    23 hours ago, Deadcode said:

    Different but faster lens will not give you same look but not because of the sensor, but the characteristics of the lens.

    Focus fall-off is lens dependant. Helios 44m-4 will give more creamy blur than Zeiss 55 1.8. Panasonic 25 F1.4 will never be as creamy as Carl Zeiss Jenna Tessar 2.8/50. But not because of the sensor size... SLR Magic 25 F0.95 will be smoother than Canon 50 1.8 STM... it's all about lens characteristics.

    I mostly agree, but I would add that images from lenses designed for larger formats often look different than images from lenses designed for smaller formats using "equivalent" settings.

     

     

    22 hours ago, Timotheus said:

    Claiming to be able to tell them apart, with the actual lens and camera data provided is bit easy, no?

    The lens for the larger format has strikingly shallower DOF.  It's amazing that some can't see that.

     

     

    22 hours ago, Timotheus said:

    Everybody agrees there can be subtle differences between different lenses, like in the example of Andrew,

    Again, the differences between the two images is striking.

     

    Also, it is often the subtleties that make the difference in imaging.

     

    22 hours ago, Timotheus said:

    the one you provided (noting that adding an APO filter is quite the change to a lens!).

    In regards to the lenses of the two images in question:

    • the focal length is an exact match;
    • the aperture is an exact match;
    • the refractive optical elements are identical;
    • the only difference is that one lens has a non-refractive filter.

    How can you reconcile the equivalency principle with such a dramatic difference in DOF, when the aperture and focal length are the same? 

     

     

    22 hours ago, Timotheus said:

     using equivalence math, you can pretty precisely predict and match the results of certain lenses on certain sesnsor-sized camera's.

    Please show how the equivalence math accounts for the dramatic DOF difference in the apodization example that I posted above.

     

     

    22 hours ago, Timotheus said:

    For evidence: see @BTM_Pix above (and countless others). 

    So, you maintain that  an equivalence comparison in which all images were shot with the same zoom lens proves that there is no difference in look/DOF between optics designed to cover different sized formats?  Doesn't one need to compare optics designed to cover different sized formats to make a valid conclusion on whether or not formats have a certain look?

     

    In regards to the "countless other" equivalency tests, most of them have been discussed on this forum, with the equivalency "absolutionists" similarly glossing over little "details," such as  comparisons done with the same zoom lens.  In almost every such test that used lenses made for different formats (except for a peculiar one linked earlier in this thread), the larger format lens always has shallower DOF.  In addition, another common flaw in equivalency tests is that there is nothing but air between the foreground and background, so there is no way to tell how the DOF rolls off.

     

     

    16 hours ago, no_connection said:

    However the lenses you showed do NOT have the same aperture which is evident in the upper right corner, I would suspect that f4 is the "mean" aperture of the apodization filter which makes sense as you loose light to the darkened edges of the filter.

    No.  The whole point of that apodization demonstration is that the aperture and focal length are EXACTLY identical -- but the DOF is very different.  If you click-to-enlarge the photos, you will see considerably more DOF differences than those shown in just the upper right corner.

     

    By the way, that apodization example originated in this article.

     

     

    16 hours ago, no_connection said:

    I do like the idea of such a filter and want to try to make one for my 50mm f1.4 that have aperture to "spare" so to speak. 

    I think that apodization filters are always internal in a lens.  I believe that Fuji had a lens in which different apodization filters could be inserted.

     

     

    16 hours ago, no_connection said:

    For what the equivalency formula is it holds true, but at the same time you have to understand what it does not do. 

    The formula only gives the "mathematical" DOF.   It does not account for DOF rolloff nor for the mushiness at wider apertures with smaller format lenses (nor for apodization).


  10. @no_connection

    The equivalency principle is not absolute if it doesn't work in every instance.  You seem to agree that it does not work in every instance.

     

    So far, almost all equivalency tests show significant differences between the look from lenses designed for different formats, with the results mostly showing shallower DOF and less mushy focus falloff with larger format lenses.  None of these tests are "pushing the extreme."

     

    There exist variables other than focal length and aperture (and aberration) that affect DOF and focus falloff.  You and others in this thread touched on one such variable -- there is a limit to the amount of optical resolution that can be crammed into an image circle for a tiny sensor.  Like many physical properties, this variable probably doesn't have a hard threshold, but instead is a matter of degree, with the image slowly degrading as the image circle decreases.   There are plenty of other possible variables, too.

     

    If you think that the only variables that matter are the ones expressed in the equivalency principle (focal length and aperture) and aberration, merely consider apodization optics.  Here are two photos taken with two Fuji lenses of the same focal length and set to the same aperture, with identical optical elements, except one of the lenses includes an apodization filter:

    a05.jpg

    Note the discrepancy in the softness of the distant background (click on the photos to enlarge them).  Every variable is identical between these two shots, except that one lens contains a filter, and yet there is an obvious difference in the DOF.

     

    The equivalency formula does not take into account all of the variables that affect focus and DOF, therefore it is not absolute.


  11. 4 hours ago, Deadcode said:

    Bravissimo brotha', you can tell a difference between a lens manufactured by Sony and a lens manufactured by Voigtlaender. Sick skillZ!

    Marvelous mister,  you completely missed the quote in my message which showed that I was merely responding to another poster who suggested that one could not "tell the cameras apart."  Sm-o-o-o-o-o-th!

     

    The striking differences between the two images do not involve the character of particular lens brands -- the discrepancies shown result from fundamental differences in DOF/focus.

     

    Actually, I am not sure that I could say which lens was a Voigtlaender or a Sony, because I am not familiar with either brand.  On the other hand, I would guess that the Sony lens is a FF lens and that the Voigtlaender is made for 4/3.  If so, the photo with shallower DOF is probably from the larger format (Sony?) lens, because such has been the case in every equivalency test so far (except for a peculiar one linked earlier in this thread).

     

    A lot of folks in this forum insists that the equivalency principle is absolute --  that lenses made for differing formats will look exactly the same, given the proper apertures and focal lengths.  Evidently, you disagree that the equivalency principle is  absolute, as your sarcasm indicates that the difference is obvious between these two lenses which are designed for different formats.

     

     

    4 hours ago, Deadcode said:

    If he use the same lens with focal reducer you will not see any difference between the two images. I have tried it.

    I mostly agree, but that point is irrelevant to whether or not the equivalency principle is valid.


  12. From this thread's excellent EOSD article:

    Quote

    Since the moment they were born, the Panasonic GH5 and other Micro Four Thirds cameras have suffered from a misconception on the specs sheet created by the smaller sensor. This misconception is that they can never replicate the look of a full frame camera. It’s not true and the pictures above prove it.

    This paragraph suggests that equivalence principle is completely true -- in other words, that there is no difference between the looks from different sized formats (more importantly, no difference in the looks from the optics designed for different sized formats).

     

     

    From the most recent excellent EOSD article on the Fuji GFX 50S:

    Quote

    The great advantage of medium format though is that you can maintain a very beautiful shallow depth of field without using such mushy wide apertures. You can stop down your adapted F1.4 DSLR lenses to F2.8 for higher resolving power and still enjoy the beautiful rendering and three dimensional depth of field of a very wide aperture on full frame.

    This passage asserts that there is a difference in looks between formats, due to the "mushiness" inherent in having to use larger apertures with smaller format lenses, in order to get the same mathematical DOF as that of lenses made for larger formats.  In other words, the equivalence principle is not valid, and optics for different sized formats yield differing looks.

     

    It seems confusing...

     

     

    On 5/25/2018 at 7:09 AM, Timotheus said:

    Agreed ;-)

    You're saying you can tell the camera's apart that took the two pictures from Andrew's original post? Nah man.

    The differences between the two images are significant.  I can tell them apart, and it appears that another poster in this thread can also discern the differences.


  13. On 5/12/2018 at 11:19 AM, Alpicat said:

    I've uploaded another video with the SD card hack:

    Great footage (and music)!  Thanks!  

     

    On 5/12/2018 at 11:19 AM, Alpicat said:

    It takes about 3 or 4 minutes to do the two tests before the sd overclock is ready to use, and then the camera runs as normal.

    Interesting.  The tests are required every time one starts the camera?

     

    On 5/12/2018 at 11:19 AM, Alpicat said:

    You should be able to shoot 1920x1080 in 5x zoom mode without overclocking in 10 bit lossless - you won't get much record time but it's feasible. I can already get nearly continuous shooting in 1800x1030 12 bit lossless movie crop mode.

    1800x1030 works for me.  What's the longest run time you've achieved with that mode?

     

    On 5/12/2018 at 11:19 AM, Alpicat said:

    Also, unsure if I mentioned that Viltrox are planning to do a 0.71x focal reducer for EF-M mount - they told me it should be out in the summer. I don't have a bmpcc speedbooster any longer so this should be a cheaper alternative, with the advantage of electronic contacts for EF lenses.

    I've heard some good things about the Viltrox focal reducers.  I have the RJ focal reducer for the EOSM with a Nikkor mount, and it was used in a couple of the shots in this test (along with the 18mm-55mm kit lens):

     
     
     
     
     
     

    All of this footage employs the All-I frames video hack in a Magic Lantern build from 2015.  Frame rates were 23.98 fps and 59.94fps (yielding 1280x720 which was scaled up to 1920x1080).  The Flaat 10 picture style was used in all shots with the first shot ungraded, but I gave a touch more snap to the contrast of the rest of the clips.

     

    The ISO was set to 800, but noise was prominent in some footage.  So, I'll probably dial the ISO back down to 100 or 200 when possible.

     

    The bit rate was boosted to 1.5x, but I got a hiccup (dropped frame or doubled frames) four seconds into one of the shots.  So, regardless of the cause, I will probably back off of that setting and bring the bit rate down to 1.3x in subsequent shoots.

     

    A screw-in ND and a polarizer were stacked, so. occasionally, there was slight vignetting.  However, there was some weirdness with the vignetting moving/changing in the middle of shots, which could be attributed to OIS, except that same behavior seemed to appear in the shots with the manual Nikkor 20mm with the RJ focal reducer.   Have to take a closer look at this apparent phenomenon.  Anyone have ideas on the cause?

     

    This test was rushed, and I forgot to change the shutter speed from 1/60th to 1/120th in the first 60fps (slo-mo) shot, so that clip looks slightly smeary.

     

    I see a little moire/aliasing and a moment of banding, but I think that this imaging quality could work for a lot of situations.


  14. 8 hours ago, BTM_Pix said:

    Main bone of contention/accusation seems to be that some posters are convinced that Cinemartin are passing this camera off as their own

    https://www.ximea.com/en/products-news/pci-express-camera-cmv50000

    The photo of the Fran certainly looks like the Ximea camera from the front.  Good find!  On the other hand, the specs don't seem to perfectly match.

     

    Judging from Cinemartin's rough sketch, perhaps they are taking the innards of the Ximea and putting them in a different box, with some hardware/software mods.

     

     

    8 hours ago, BTM_Pix said:

    even outright racism with someone claiming because the designer is Spanish it will never get finished on time !

    I wasn't aware that there is such bigotry against those of the Spanish "race."

     

     

    6 hours ago, Grimor said:

    it's the same cinemartin brand as those suspicious "cheap monitors" that never came to be sold and that were supposed to be rebranded chinese product?

    Not familiar with Cinemartin, but a lot of the stuff that get's touted on this forum is re-branded product.


  15. 21 minutes ago, kye said:

    Who knows how much thought or market research goes into these things...  or who their target market might be.

    The configuration that I suggested above (with the smart, reinforced M4/3-to-EF adapter) does not preclude the clueless EF lens user market... nor does it preclude any market.  In fact, such a smart, reinforced adapter configuration allows the most versatility in regards to marketing, without any sacrifice to the EF lens market.


  16. 17 minutes ago, kye said:

    From the article - "The choice of lens mount is likely due to the fact that Yongnuo only makes lenses for Canon and Nikon, but no Micro Four Thirds glass."

    Yes.  I read that, but that makes even less sense than BMD and Panasonic offering only EF mounts (or longer) for their S35 cameras.  What if somebody wants to use a M4/3 lens on the Yongnuo M4/3 camera?  or, what if somebody wants to use a speed booster, tilt-shift adapter, c-mount lens, etc. on the Yongnuo M4/3 camera?

     

    All they have to do to easily solve those dilemmas (and probably sell more cameras) is to start with a M4/3 mount and supply the camera with a smart, reinforced M4/3-to-EF adapter... and the camera will still take the Yongnuo lenses.


  17. 11 hours ago, UncleBobsPhotography said:

    But the 9V is delivered through QC, which can boosts the voltage to 9V regardless of whether the source battery is at 4.2V or 3V. It would have been different if we were talking about an actual 9V battery.

    The AC adapter delivers 9V.  If there is no voltage regulator inside the "dummy" battery, then the camera is running off of a 9V supply.  If the there is a voltage regulator in the dummy battery, then the camera is likely running off of ~7.2V.   Either way, there is likely extra heat being generated inside the camera (compared to merely running off of a 7.2V internal battery), which could result in extra noise.

     

    Best to keep everything inside the camera at nominal voltage.

     

    Not familiar with "QC."


  18. 5 hours ago, Vladimir said:

    as you can see CP-W126 itself have 9V marking

    I see it.

     

     

    8 hours ago, UncleBobsPhotography said:

    It's not uncommon for a 2 cell 7.2V battery to have a voltage up to 8.4V when fully charged, so 9V is probably within the tolerance limit of the camera. On the other hand, it's not a bad idea to be on the cautious side.

    Yes, batteries' voltage is higher when fully charged.  So, likewise, if you start with a fully charged 9V battery (as opposed to a 7.2V battery), you will probably see voltages higher than 9V -- significantly higher than the 8.4V peak of the fully charged internal battery.

     

    Again, it's a good idea to start with an external battery that has the same voltage as the unregulated internal battery.   Thus, you know that you have enough voltage for the camera to properly function, while you will not be unduly increasing the camera's internal temperature (possibly causing extra noise).

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