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Posts posted by no_connection

  1. that is not a 24-200 f2.8-f4.5

    it's a 9-72mm f2.8-f4.5

    or 24-200 f7.4-f12.4 (opening is 18mm high which would be f11 so there is likely some errors somewhere in there or it's not optimal in size)
    At the wide end they could have made it a LOT faster than it is.

    Front element would have to be 44.4mm which is as large as the entire lens assembly. Or 76% of the cameras height.

    25 minutes ago, Andrew Reid said:

    I would have liked a longer zoom but not 200mm at all costs. 24-135mm F2.0-2.8 would have been great. 

    That would have been a 24-135mm f5.4-f7.5
    or 8.9-50mm f2.0-2.8

  2. I have read the blog for, well I have no idea how many years, 4+ but probably more. I have always liked the idea of using "cheaper" stuff in a way that is compare or beat "real" equipment. Creative ways to use things.


    What I always wan in reviews is how the thing is to use, what will be annoying when you use it a particular way and what it can do in a special way.
    Or is the EVF going to bug me, do I have to jump through hoops to have decent chance to focus manually and so on. Proper numbers for rolling shutter on every mode. Preferably on 25p and 50p. You know the stuff most other reviewers don't notice or don't care about.
    And stick some c-mount lenses on it and crop that thing!

  3. By the looks of it it's 100% digital.
    Simple step by step: use auto exposure, mess up levels at import, mess up grading badly, slap a filter on it, pretend it's working as intended.

    By evidence if you cut things fast enough ppl won't notice how incredibly bad it really looks.

    Anyway enough about that.
    It looks like some shots where cropped and re framed/moved in post, lot of the closeup looks a little too close to be shot that way, but who knows.
    I think it's the time skip that makes the "home look" work for telling the story.
    I'm not a super fan of the too close up and the added shaking filter makes some of the pans look really odd if you look closely.

    smile dear.JPG

  4. 17 hours ago, tupp said:

    On the other hand, the background is softer with the APD filter in every set except for the one at f5.6.

    Softer and size are two different things.


    17 hours ago, 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. 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.


    12 hours ago, Don Kotlos said:

    print it on a translucent paper.

    Problem is it's not exactly optical grade, maybe get some of that meant to print on t-shirt and then transfer by heat, maybe even sprinkle toner on a glass filter and bake it.
    We should make a thread bout it somewhere.

  5. 4 hours ago, tupp said:

    No.  The whole point of that apodization demonstration is that the aperture and focal length are EXACTLY identical -- but the DOF is very different.

    Then the focus or object distance is not the same.
    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.


    4 hours ago, tupp said:

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

    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.


    4 hours ago, tupp said:

    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.

    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.

  6. 8 hours ago, tupp said:

    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. 

    Look, if you flip the terms of the equation the only thing equivalency will tell you is how to get the same diameter lens with different focal lengths. It's simply a number that relates things to each other and make them comparable.
    You are 100% correct in that I think it's not that relevant and as you have shown lens construction or "features" is more important. 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. 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.

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


  7. It is absolute. But for some reason lens manufacturers don't seem to follow the theoretical magic lens that was used to make it.

    And since lenses are made with other aberrations in mind large aperture wide angle lenses will always struggle for small sensors. Try make a lens for a phone sensor with the same DoF as a FF 50mm f1.4. You might argue that it's an extreme example but does show there is a upper limit (or lower) so it has to follow a line or curve of some sort. And when pushing that extreme FF will always win out in that regard. Does it matter when you stay inside the extreme? No, the equivalency is happy to work just fine when not pushed to the edge of oblivion.

  8. Just put a M.2 slot. It's not like the offload not gonna be fast enough anyway. Maybe a compatible port to interface the PCIe directly. Altohugh I guess USB3 is decent enough.
    Granted form factor may be limiting since ssd are usually longer but I don't see CFast or SD being better than for example a 1TB fast ssd. But that 2GB write speed is kinda tempting tho.

  9. My take on it, if you don't have enough horsepower and can't put at least 24p at 4k then don't include it. If they loose sales because the 15p 4k isn't there then they really are tricking customers.

    My guess it they can't read out the sensor fast enough to clear an entire frame before next one is needed.

  10. 7 hours ago, KnightsFan said:

    No, we were talking about pixel vignetting, which is caused by pixels being recessed.

    If you look at Nikon lenses the large flange distance means the angle can't be too high simply due to the distance. (ignore the wonky ultra wide angle that had a long element stick in under the mirror).

    Sony on the other hand had a huge problem with the a7s giving a red cast with some wide angle lenses.

  11. 1 hour ago, KnightsFan said:

    I'm probably wrong, I'll need to read up more on lens design. It was an intuition based on the fact that scaling an object doesn't change any angles--but again, I am not sure it's right. I hoped someone could explain why it was right or wrong.

    Are you thinking about the distortion that you get with planar projection where the edge get "stretched" which do worsen as the angle get wider?


    Also things get really hard as aperture increases so a 50mm f2 is a lot easier than a 25mm f1. So a large aperture lens, especially wide angle it reeeely hard. Which is probably why you don't see many of them.

  12. 3 hours ago, canonlyme said:

    I'm sry but I don't think you are right.

    Then you are ether reading me wrong or understanding me wrong.
    f is literally the ratio of focal length to diameter. (I called it apparent front element as it shrinks when you stop it down).

    3 hours ago, canonlyme said:

    Saying that a 50mm m43 lens really is a 100mm ff lens instead, just so that you understand the equation better, is wrong. 

    That is why I don't like this equivalent thing at all, not even when using a speed booster. They would have the same field of view tho.


  13. While 2x16GB is indeed a great start, RAM price is not the nicest nowdays. But I guess that is what happens with a planned shortage to drive price up. Going to be interesting to see what happens with that lawsuit, if it even change anything since it's not the first time it happened.

    16 hours ago, OliKMIA said:

    Having two sticks allows for some redundancy if one stick fails. With one stick only your PC will be down in case of memory failure and it could be hard to troubleshot the issue. With two sticks you simply remove one after another and restart the PC to check what is going on.

    This is why I like ECC in a workstation, granted I have not heard of anyone having RAM problem in years unless you count lightning strike or other causes.

  14. I did not watch whole video but so far it's a nice explanation of what has already been said in the thread.

    2 hours ago, canonlyme said:

    When talking about final aperture on a lense, you have to include the fact of which format the lens was originally made for.

    It kinda does not matter what format or sensor size since that is not part of the equation. It's a common misconception that m43 lenses can be smaller than full frame, and while it can be smaller and keep the same field of view but not change the f stop. say a 25mm f1.4 is a lot smaller than 50mm f1.4. If you make the two lenses equivalent they would be exactly the same width. Granted if you found a magic material to make lenses from it would only be half the length, but if you look at the lens in the article it's not exactly 18mm deep.
    Now this does not include any vignetting caused by the back element edge occluding the front element so the image circle is made small. (ever wondered why the g-master lens is so large to keep the bokeh balls round? that is one of the reasons)


    2 hours ago, canonlyme said:

    Does a full frame lense of 35mm 2.8 change its aperture when you adapt it with a simple adapter (no speedbooster) to m43? No it doesn't

    While that is true you can see in the video that DoF do change simply because the image is viewed in a different size. You could just put a large black border and displayed it on a small square and it would be exactly like on full frame, minus a lot of content around. (meant to be a poke at letterbox if you are old enough to remember all the butchered DVDs).

  15. 1 hour ago, noone said:

    I would say it does change the lens in that it becomes part of the lens as a teleconverter does.     It isn't part of the camera anyway.

    It depends on how you look at it, but if you indeed look down just a teleconverter you see a smaller sensor than without, and as far as I see the converter is not part of my eye.

    1 hour ago, noone said:

    I believe some faster zoom lenses were actually made by adding a focal reducer to a normal lens in the lens as part of the construction.

    A lot of lenses is made like that from what I have seen, in one way or another. 50mm f1.4 for example.
    And some with teleconverters built in too.

    1 hour ago, noone said:

    In any event, this is what Metabones who makes the Speedbooster says (Speedbooster is a focal reducer).

    Does cropping increase the focal length of a lens? A speedboster is just decreasing the area that the image is projected on as far as the sensor see it, or from the lens perspective it increases the area of the sensor. I'm not saying calling it a focal reducer is wrong, per say, but for me it makes more sense to look at it that way since you don't change much of the lens properties. And it removes the need to "convert" any numbers.

  16. A speedbooster does not change the focal length or the aperture of a lens. All it does is changing the apparent sensor size. And so does a teleconverter.

    If you look down the barrel of a teleconverter you see the sensor appearing at a smaller size. If you look at it this way it's no longer a problem to grasp the concept.


    The only two things that change DoF at the lens level is apparent front element size and focal/object distance.
    The only factor that remain is viewing size. Or viewing angle as seen by the eye. (iPhone screen at arms length will have longer dof than the same image viewed with the phone pressed to your nose). Or circle of confusion or what ppl normally call it.

    Sensor size and the needed focal length and corresponding f-stop is only a resulting number that depends on another number and as shown can be interchanged with the same result.

    And on a side note, the light gathering is directly related to apparent front element size. The focal length determines how large area that light appears on. And if you know math, it should not come as a surprise that regardless what you do, it's the same amount of light for any chosen lens diameter and field of view, just spread out over a different sensor area.

  17. I don't see 4096x2160 in the table above. So the assumption isn't that off?


    The dynamic range also makes sense, since I read it that it is done in HD. and scaling 4k to HD would gain one stop of DR from noise being reduced.

    What I don't like about the noise test is "All measurements were made in HD mode (1920x1080). Noise levels in UHD and 4K modes ought to be similar."

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