Jump to content

Andrew Reid

Administrators
  • Posts

    14,798
  • Joined

  • Last visited

Everything posted by Andrew Reid

  1.   Again... not true when you look at it on a per pixel level at 1:1.   If all is equal with the generation of sensor, and pixel density, then a crop sensor is merely that... a crop of a full frame sensor and in that crop is the same quality of image, same pixels, same intensity of light capture, same signal to noise ratio, to pretend otherwise because you are taking the whole sensor and shrinking the image down in post is a bit daft really.
  2.   Gather more light yes but how much you gather ACTUALLY depends on the pixel architecture!
  3. Reducing an image in size from any sensor crop allows you to think of the sensor as one giant pixel but the problem is not all sensors are created equally.   You can have the Blackmagic sensor in the Production Camera, a large APS-C sized sensor with just 8MP and yet above ISO 400 it is really noisy because the photosites that actually do the light capturing are so small, and around them is a load of circuitry for global shutter readout taking up room on the sensor, that cannot be used to capture light!   You can have the 1" sensor from the RX100 Mark III which is back illuminated and very good micro lenses, no gaps between pixels, crowded out with 20MP on a small surface area and it ends up being as clean at ISO 1600 as the much larger 24MP sensor in the NEX 7 from a few years ago, because the pixel architecture and design is more modern, the micro lenses better, the readout circuits cleaner, less noisy A/D and so on...   So what is this total nonsense calculating ISO with the crop factor of the sensor.   The OP is trying to over simplify and combine specs so that they are universal with all cameras. It can't be done. You have to measure each component of the camera separately. Aperture is a separate spec to sensor size. Focal length is separate to sensor size. A 24mm is a 24mm! Whilst it may help to think of focal lengths multiplied by crop to get the angle of view (we all can use this to figure out what a 12mm looks like on a 2x crop sensor can't we?) it doesn't help when people try and change the spec of the lens based on something that is actually unrelated and a totally different thing, a different part of the camera.
  4. I am a big fan of the full frame look and large sensors but facts are facts guys.
  5. Say if we follow his logic and apply crop factor to ISO...   5D is an old camera, can barely do clean ISO 800 but hey... BIG SENSOR!   GH4 is a new camera, does clean ISO 800 on a 2x crop sensor.   By this logic 800 is actually 2x... so as noisy as ISO 1600 on the 5D Mark 1's full frame sensor from years ago...   Nah doesn't work does it!?
  6.   It's not about math or his example images, it really isn't. He uses very little maths and it is mainly his other examples which aren't backed up by any maths at all that are so wrong. What he is saying about applying crop factor to ISO is just plain wrong. It is like calculating the speed of an aircraft based on how windy it is outside, and ignore all the other things. The examples he's grasping at are bad. The reality is very different to what he describes in the video.   The intensity of light hitting the pixels and the design of those pixels are what matters when it comes to sensitivity, ISO and aprture, NOT the area of capture or crop factor of the sensor!   This is infuriatingly obvious stuff!
  7.   Dude this is wrong.   A full frame sensor will only take advantage over the larger image circle projected by the lens if the pixel architecture is sensitive enough. If you have small pixels with big gaps in-between or too many pixels and too small pixels then your theory will snap like a brittle stick in the dog mouth of reality.   For example a smaller crop sensor with larger pixels than a larger full frame sensor will capture more light.   Per-pixel quality matters the most.   Therefore you cannot simplify this down to simply 'a larger sensor captures more light' like the idiot in the video has got everyone doing. Ridiculous AND annoying at the same time.
  8. When you attach a lens to a crop sensor, the lens remains identical. The image is identical, but for the crop into the image circle.   He says the whole photographic system of aperture, ISO, focal length makes no sense. SAY WHAT!?   Aperture and focal length relate to the lens only. Why should they apply to a combo of sensor size and lens, as the video suggests it should?   A 2x crop factor helps when it comes to figuring out the angle of view. 12 x 2 = 24mm. That's about it.   The aperture doesn't change. The exposure doesn't change.   Applying crop factor to ISO is a huge mistake. That a larger sensor captures 'more light' ignores the fact that large sensors can still have small pixels due to very high megapixel counts or large gaps in-between pixels.   The ISO does not crank up on a smaller sensor because it isn't receiving as much light as a larger sensor.   You have to look at the sensor on a per pixel basis. The size of the pixels.   Take a 24MP full frame sensor and cut out 16MP from the middle to give you a crop sensor.   Look at both images at 1:1...   See a difference? No. So why does this guy suggest otherwise?   Because what he is neglecting to mention is he's not looking at the images 1:1, but downsampling the 24MP to 16MP, then comparing to a 16MP crop sensor. The downsampling of course makes for a cleaner image.   This is also where DXOMark goes wrong very often. They include the downsampling in their calculations too.   So a 36MP sensor would do very well in low light even if it was noisier on a per pixel basis. Look at their low light results for the 5D Mark III vs D800. We know the 5D Mark III has better high ISO than the D800 yet DXOMark somehow haven't managed to show this in their scores.   What matters is pixel size, pixel architecture and readout noise... Not sensor size.   The Blackmagic Production Camera is absolute proof that this guy's theory fails the reality test.
  9. The Speed Booster effect has no relation to the size of the sensor. It has a relation to the reduction factor of the Speed Booster and how much the image shrinks, but not the crop of the sensor behind it. The is using a very bad example and technically it is very misleading and confusing.
  10. Technique, tips and software - all the how to stuff - that is not subjective and a good place to start with this thread I think.
  11. All this stuff is either wrong technically, or a silly way to look at things... New readers to this thread, all I can say is beware!
  12.   This is also false.   Speed Booster works by brightening the image projected at the sensor. The light from the lens is concentrated into a smaller area. It has nothing to do with how far you crop into it. If you took the centre of the image in photoshop and cropped it, you do not 'lose light' and the image does not darken does it!??!
  13. Referring to the video. It has more holes in it than a block of swiss cheese.   He says a large sensor captures more light, without mentioning the crucial SIZE and NUMBER of pixels. It is the size of the pixels and how many there are that gives you your resolution and dynamic range. The Blackmagic Production Camera for instance has a larger sensor than the GH4 but sucks in low light because it has small photosites due to global shutter circuitry around each pixel taking up a lot of room. He has grossly oversimplified things in that video through lack of basic knowledge.   He is multiplying aperture by crop factor to give an equivalent depth of field, this too is bollocks.   F1.2 is F1.2. At the same focus distance and focal length you will get the same shallow DOF with a 50mm F1.2 on a small sensor as you would do on full frame. The difference is that to maintain the same framing, the small sensor camera has to move back from the subject, and the focus point shifts backwards towards infinity, which lessens the separation between the subject and background making it appear that the lens is giving a less shallow DOF.   He also really stupidly in his Canikon love affair doesn't seem to mention that F1.2 is as bright as F1.2 no matter what the sensor size is.   F1.4 does not = F2.8 with a 2x crop sensor in terms of exposure or light transmission.
  14. Cinema5D had a famous anamorphic thread which ticked along very nicely for 2 years until it died. I'm a big fan of sticky things :)
  15. This is my favourite of the small, compact LED panels with good battery life. I like it mainly for the variable colour temperature control.   http://www.eoshd.com/content/9867/switronix-torchled-bolt-variable-temperature-led-light-review   If you just want a harsh but bright white light and are shooting raw, so can heavily colour correct the white balance in post then this is a good deal for cheap! 
  16. If this thread takes off then I'll make it into a sub-forum. Having it as a sticky thread is a good way to get the flow of conversation started as sub-forums are more 'hidden away'.
  17.   I've been trying James Miller's settings around that and it does indeed work wonders for the blacks. Very smooth.
  18. The official topic for discussion of Magic Lantern raw video recording on Canon DSLRs.
  19. Andrew Reid

    Lighting

    The official EOSHD forum for discussion of lights, lighting, both creative techniques and the hardware!
  20. Andrew Reid

    Grading

    The official EOSHD thread for discussion of grading and colour correction. Techniques, software, codecs, etc.
  21. Andrew Reid

    Lenses

    The official EOSHD discussion thread for all things lens related!
  22.   Who said anything about street videography? If your cast is in the zone and ready to go, but the camera man is fiddling with his live view and mirror flipping up and down, it's a pain...
  23. This thread is in the wrong place.   http://www.eoshd.com/comments/forum/21-creativity-and-ideas/
  24. What's the point of slightly better image quality if you miss a shot entirely due to having to quit movie mode simply to set the required aperture?
×
×
  • Create New...