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View Full Version : difference between fs100 sensor, 5d mk2 and af100?



corycross
05-01-2011, 09:02 PM
Its super 35( fs100).. which is smaller than the 5d sensor(full frame).. correct? And the af100 is a 4/3 sensor.. so its smaller, less depth of field.. but from Philip blooms review, it appears that the fs100 gets way better low light..

Am I right here, or am I missing something? Thanks

corycross
05-01-2011, 09:07 PM
http://www.creativevideo.co.uk/images/uploaded/sensor_table.gif

Sam Scoggins
05-01-2011, 09:48 PM
The sensor in the FS100 (and F3) was designed from the ground up as a digital video sensor, it is not compomised by the needs of still photography. It has less photosites than the AF100 and 5D11, but those photosites are much larger, hence it is more sensative to light.

pulpfiction007
05-01-2011, 10:24 PM
The sensor in the FS100 (and F3) was designed from the ground up as a digital video sensor, it is not compomised by the needs of still photography. It has less photosites than the AF100 and 5D11, but those photosites are much larger, hence it is more sensative to light.

Exactly! If the 5D sensor only had 4MP it would be so sensitive it would need ND filters in the dark, but as it is it's packed with mega pixels for stills shooting. The low light does not reach it's full potential, even though it's still very good.
Look at the D3S with it's full frame and 12MP sensor for proof of the lower MP being great for low light performance. Bloom said out of the VDSLRs nothing can touch it (sensitivity wise).

dcloud
05-01-2011, 10:33 PM
DOF wise
Af100 has roughly 1/2 stop difference to an s35
S35 has 1 1/2 stop diff to 5D
Af100 has 2 stop diff to a 5D

imag
05-02-2011, 07:01 AM
Note that the chart above is not precisely correct in the case of the F3/FS100 chip. Sony's own literature lists the chip as: 23.6mm x 13.3mm. This makes it slightly smaller than standard Super 35 with a wider native aspect ratio.

Something to keep in mind when figuring your crop factors.

Literature reference here: http://www.sony.co.uk/res/attachment/file/59/1237480643259.pdf

imag
05-02-2011, 07:11 AM
Note also that the DX chip in that chart is not to scale. It is shown wider than the Super 35 chip when it should be narrower.

Wendt
05-02-2011, 11:09 AM
Which camera would have a more shallow DOF: FS100 with a F4 lense or a AF100 with a 2.8 lense? If they are about the same wouldn't that save some money on lenses by buying f4 lenses? Also, if a F4 lense was used for daylight shooting would I need less ND filters to open it up? Thanks for your thoughts.

Barry_Green
05-02-2011, 11:11 AM
Yeah, that chart is wrong on all the S35 cameras. It's using the frame size of S35 film, which is a 4:3 aspect ratio and almost 25mm wide, but none of those cameras have a sensor anywhere near that large. S35 film is 464mm2, but the F3/FS100 are 314mm2.

In terms of "crop factor", that's never the easiest thing to calculate because it doesn't take into account the inherent aspect ratio difference. 35mm still film is a 3:2 aspect ratio, or 1.5:1. The video sensors are 16:9 aspect ratios, or 1.78:1. If you wanted to calculate a "crop factor" based on just using the width, the S35 cameras would be a 1.53x crop.

It'd be far more appropriate to recategorize all those "S35" cameras under the APS-DX sensor size, because that's closer to what they really use (at least in width; in height they're shorter, again due to the aspect ratio differences).

Wendt
05-02-2011, 11:24 AM
Which camera would have a more shallow DOF: FS100 with a F4 lense or a AF100 with a 2.8 lense? If they are about the same wouldn't that save some money on lenses by buying f4 lenses? Also, if a F4 lense was used for daylight shooting would I need less ND filters to open it up? Thanks for your thoughts.

anyone?

Barry_Green
05-02-2011, 11:47 AM
The AF100 would be shallower in DOF in that scenario. The difference between the AF100 and the FS100 is about 1/3 of an f-stop. So you'd have to open up the FS100 to f/3.2 to get the same DOF between them.

imag
05-02-2011, 11:50 AM
Absolutely. When I started delving into which lenses I wanted to get, I built a little spreadsheet to calculate the relative proportions in the horizontal and vertical directions separately. That allowed me to really figure out which lenses will get me the FOV I want. In the end, the FS is really not *that* much different than APS-C.

Barry_Green
05-02-2011, 12:10 PM
Absolutely. When I started delving into which lenses I wanted to get, I built a little spreadsheet to calculate the relative proportions in the horizontal and vertical directions separately. That allowed me to really figure out which lenses will get me the FOV I want. In the end, the FS is really not *that* much different than APS-C.
It is barely *any* different from APS-C. It's a difference of about 7%.

imag
05-02-2011, 12:31 PM
If anyone is interested, I just threw the calculator online here: http://www.is-movie.com/LensConverter.xls (right click and download target)

Note that blue boxes represent areas to make changes - everything else is calculated from those. You can type in a lens size in any of the converters below and see the equivalent lens sizes in the other formats. Everything is calculated in the horizontal, vertical, and diagonal directions independently. It's probably overkill, but I was sick of seeing a bunch of ambiguous and contradictory "crop factors". If I'm dropping a bunch of cash on a prime lens for a camera I can't fit it to, I want to make damn sure it will look the way I expect.

Stab
05-02-2011, 02:21 PM
Does anyone know how much the 7D/60D/etc 'use' of their sensor in video mode? Does the shallow DOF come from the sensor size as it is, or do they use a smaller part of the sensor while filming?

I read that the Red One in the 2k mode only uses a small percentage of the sensor as opposed as shooting in 4k mode. How's that with the DSLR'S?

xenogears
05-02-2011, 03:32 PM
I donīt want create a thread to ask this, so here goes:

Someone knows how the Image Stabilization works in the FS100? is in body stabilization or lens stabilization?.

Cheers

Barry_Green
05-02-2011, 04:30 PM
Does anyone know how much the 7D/60D/etc 'use' of their sensor in video mode? Does the shallow DOF come from the sensor size as it is, or do they use a smaller part of the sensor while filming?
Full width, but cropped height to get the 16:9 aspect ratio. Their sensors are 3:2 so they crop off the top and bottom to make 16:9.


I read that the Red One in the 2k mode only uses a small percentage of the sensor as opposed as shooting in 4k mode. How's that with the DSLR'S?
Apples, oranges, and kumquats. All the DSLRs always use the full size of their sensor, but they only read out a small percentage of the total pixel count (usually about 1 in 9 pixels or thereabouts). The Red always reads out 100% of the pixels, so for the different frame sizes it changes the absolute surface area of the chip it is scanning.

evilthought
05-03-2011, 01:02 AM
I donīt want create a thread to ask this, so here goes:

Someone knows how the Image Stabilization works in the FS100? is in body stabilization or lens stabilization?.

Cheers

Lens (if the lens has IS)

natums
05-03-2011, 01:16 AM
Apples, oranges, and kumquats. All the DSLRs always use the full size of their sensor, but they only read out a small percentage of the total pixel count (usually about 1 in 9 pixels or thereabouts). The Red always reads out 100% of the pixels, so for the different frame sizes it changes the absolute surface area of the chip it is scanning.

So are you saying it basically crops the sensor for lower resolution instead of just scanning every other horizontal line like most other cameras? This would prove better for aliasing I guess but then you are basically working with a 2x crop value in 2k files? I have only had the bare minimum hands on time with a Red and didn't know that. This would have a seriously negative repercussion of DOF...

Barry_Green
05-03-2011, 09:30 AM
Yes, the Red crops or "windows" the sensor. In 4K mode the area of the sensor it uses is about the same size as 35mm movie film. In 2K mode it's about the size of 16mm movie film. And yes it has the negative repercussion on DOF and FOV that you would expect. It becomes, in effect, a smaller-sensor camera. But simultaneously it gets better rolling-shutter performance and higher frame rate capability too.

natums
05-06-2011, 05:19 AM
Interesting, learn something new every day. Thanks Barry!

nyvz
05-06-2011, 10:22 AM
The AF100 would be shallower in DOF in that scenario. The difference between the AF100 and the FS100 is about 1/3 of an f-stop. So you'd have to open up the FS100 to f/3.2 to get the same DOF between them.

My calculations say its closer to 3/4 of a stop:

23.6mm / 17.8mm = 1.33x crop

1.33^2 = 1.77 stops = .77 stop difference

Let me know if you get something different though. The GH2 on the other hand is closer to 1/2 stop with its slightly larger m43 sensor.

cgold
05-06-2011, 10:59 AM
I believe the AF100 has the same "slightly larger" sized sensor as the GH2.

nyvz
05-06-2011, 11:22 AM
I believe the AF100 has the same "slightly larger" sized sensor as the GH2.

It seems that it does, but the active area is smaller. From what I understand, they both have the same 19.3mm wide sensor, but the GH2 uses a 18.8mm wide active area, AF100 17.8mm, and m4/3 standard specs are 17.3mm wide.