Faster FPS with RAW?

[castrol]

So I finally decided to make the switch to shoot in RAW. I was shocked to find
that when I am shooting in RAW, my FPS is MUCH higher than when shooting
otherwise.

Is this because the camera isn't having to apply the JPG compression and
all that jazz to each shot?

Just curious. It was a surprising detail I was not expecting.

 

[Digital Matt]

The FPS should not change between raw and jpg. What will change is the amount of shots you can buffer. It might seem faster, but I doubt it is. I could be wrong though.

 

[castrol]

The FPS should not change between raw and jpg. What will change is the amount of shots you can buffer. It might seem faster, but I doubt it is. I could be wrong though.

There is a definite, audible difference in speed between the two. There is no
doubting that. Move it to RAW and its CLICK.CLICK.CLICK.

Back to JPEG and its more like CLICK...CLICK...CLICK.

Of course, I am only doing a 3 shot burst so I am not sure about the buffering.

 

[darich]

You're right Matt.
FPS will be the exact same.
The buffer size is set at whatever level the manufacturer decides and when it's full, the fps will drop dramatically to the speed that the buffer info is written to the card.
It'll be fewer images in a burst in RAW, because the file sizes are larger. Larger file sizes means fewer can fit in the buffer so it'll fill in fewer frames and therefore quicker since the FPS is the same.

I used to have a 20D and on that camera if you shoot in highest quality jpg the buffer allows something like 23images before it's full and the frame rate drops from 5fps to around 2fps. However, if you lower the quality of the jpeg by one step then you can shoot continuous jpg until your memory card is full or the battery dies, whichever comes first.

But your fps is constant regardless of whether you shoot small jpgs or RAW images. The buffer will filled after a different number of frames though.

 

[castrol]

Then I am baffled.

My CF is an 80X 2GB card. Same card, same shots sitting here at my desk
shooting under the same conditions.

I have always read the D70 would shoot 3FPS, but it never has. Seems a lot
closer to 3FPS when shooting in RAW.

I wish I could explain it better. Very odd.

 

[Big Mike]

There is a definite, audible difference in speed between the two. There is no
doubting that. Move it to RAW and its CLICK.CLICK.CLICK.

Back to JPEG and its more like CLICK...CLICK...CLICK.

Are you maybe holding the camera with a different view? JPEG would be slower if the scene was significantly darker...causing a shutter speed longer than 1/3 of a second.

 

[castrol]

Are you maybe holding the camera with a different view? JPEG would be slower if the scene was significantly darker...causing a shutter speed longer than 1/3 of a second.

Same shot, same angle, actually just sitting on my desk pointing at the clock.

Make the change and shoot it exactly the same way without even picking
up the camera. No other changes. Wonder if the second hand on the clock
would show it? Heh.

 

[Sw1tchFX]

That's really wierd. My D70s doesnt' do that.

 

[TBaraki]

I've noticed the same thing on my D70s. I just ran a test to confirm. 1/500s wide open. First in RAW then in large fine Jpg . RAW was much quicker for the first three frames, then settled down to the same rate as the jpg. The difference is really quite drastic. The jpg trial remained at a constant slower rate.

Curious...

 

[castrol]

I've noticed the same thing on my D70s. I just ran a test to confirm. 1/500s wide open. First in RAW then in large fine Jpg . RAW was much quicker for the first three frames, then settled down to the same rate as the jpg. The difference is really quite drastic. The jpg trial remained at a constant slower rate.

Curious...

SWEEEEEEET!! I thought I was losing my mind. Thanks for backing me up
on this one. I wasn't sure how I was going to get a video or sound clip up
so people could hear the difference.

I was doing 3 shot bursts, I didn't go past 3 though. I would be willing to
bet mine will do the same thing.

 

[usayit]

Hmm.. interesting.. theres more processing required for JPEG but on the other hand RAW files are larger thus more writes to get them to the media card. The size of the internal buffer, the speed the camera can perform a write, the processor operating on the JPEGs, and the speed of the media card itself are all factors. What you are describing leads me to believe that the camera's internal processor working on those JPEGs are the bottleneck and not the speed at which it can offload to the media card. Switching to RAW removes that bottleneck... just a guess.

 

[darich]

if it is true then it's very strange.
it would be the first time i've ever heard of a computer processing a few larger files quicker than it can a couple of smaller files.

if it works then take advantage of it!!!
:thumbup:

 

[usayit]

... but RAW requires less processing... no compression.. no sharpening.. no contrast and saturation adjustments. Its just straight data from the sensor to the internal buffer then writes to the media. While JPEGs require data from the sensor, compression, sharpening, contrast, saturation, write to the internal buffer then writes to the media.