|
Forum: Pentax K-1 & K-1 II
08-30-2016, 12:35 AM
|
| |
This may be to do with motion picture cameras but all the same laws apply and it quite nicely illustrates all the considerations of crop and full frame
Understanding Sensor Crop Factors
i think i mentioned this before but all film makers quest for S35 or even FF to shoot in (FF is basically vista vision so something like North by North west was shot in FF)
and if you look at the reaction to the new Canon 5d mkvi ( which is not good it has 1.74 crop on the video all the canon video users have gone in to meltdown)
the main reason the 5d became so popular was for video you got the full frame look in HD video....not so much its stills capabilities
with the release of the MKVI the video instrest in this camera will fall away due to the massive crop and ....you will be seeing SONY pick up the slack in the Full Frame video market
so you can argue over the technicalities of FF v APS-C all day long but i think its more a Look than a definable technical aspect of either format
as a filmmakers we want S35 and FF and not crops its that simple ...and that is why FF sensor will be coming more and more to market
|
|
Forum: Pentax K-1 & K-1 II
07-28-2016, 03:21 AM
|
| |
There are lots of reasons you need to shoot at 8k and 6k irrespective of the screen being available to view it
first off as you know when you shoot with any bayer sensor you lose resolution the rule of thumb is
Resolution of a Bayer pattern sensor is 0.7 * .....ish it varies some are higher some are lower
So if you shoot with a Black magic 2.5k film camera the raw image from the sensor is 2400 x 1350 so you divide 2400 * .7 you get 1680 so thats the true resolution of the image after be debayered
higher end cameras like an arri will shoot at 2880x1620 which once the image is debayer will give you true HD and true 2k
ok so now we have 4k as you will note most of the high end camera will have a sensor spec of 4.5 or 4.6 k so when this is debayered it will give true UHD ( which is not actually 4k)
that's fine but the bigger we go with the image, the downsample produces sharper and better picture it also give us the opportunity to reframe and stabilize the image correctly
Pentax brilliantly built in super resolution in the k1 and other k cam,s which is another way of getting more detail in the image ( i won't explain how this works i,m sure you know) ...and as we know it won,t work for movement hence with movie camera we need to get back the detail with a much bigger image capture and downscale
you can definitely see the difference better 4k and 2k in a cinema ...however it needs to be projected correctly and originated in 4k .....eg the new starwars film was finished in 2k and for 4k projection its uprezzed and you can really see how soft that is on a 4k projection
you want to go and see 4k projection of interstellar i know from the guys who did the finish and that's is a full 4k delivery and looks amazing
i have done quite a few 4k cinema jobs myself and i shoot at 6k on Red all the time Red footage is compressed so the storage requirement aren't as bad as you think i shot with 4 reds at 6k while back at 5:1 compress which is the standard unless you're doing effects work we shot 6TB of data over 2 days
in film world we are after bigger sensors for many of the more subtle reasons mentioned , subject separation, light gathering .. the bigger the image the the better for us ,look at something like the revenant some of which was shoot using the arri 65 which is like filming on medium format
also just a note the new rogue one star wars film is also being shot on the arri 65
any way FF is great, medium formats even better i see people going on about how good crops sensors are there great to a point and from a purely commercial aspect they are cheaper to make than a large sensor ...hence they are everywhere
|
|
Forum: Pentax K-1 & K-1 II
07-27-2016, 03:33 AM
|
| |
interesting thread
just a note every major film camera manufacturer , RED, ARRI, SONY and blackmagic is build bigger and biggers sensors for their camera,s the new Dragon sensor is 40.96mm x 21.6mm and you can film FF to deliver 8k video
makes you think that if crop sensor deliver the same things a full frame can ....why would they spend millions in research to build these ...and why is the demand so high for these
i mean all film/digital made up of is 24 still images shot in a row in second ..i,m sure some of the same science and maths applied to still and film image :-)
|
