Help! Frame rate crisis.

[Mark Davis]

Just got the camera... and went straight into a shoot. Big mistake. This camera is a disaster without ND filters, which I didn't have on hand. The pictures were massively over exposed. I had to put the shutter speed on auto to get an exposure. It was recording at 100 or 200 fps. The pictures look good on playback but make an awful stuttery conversion into Apple Prores.

Is there any software or techniques that can give me a smooth picture when converted into Prores or similar??

Any advice appreciated

[Shaun Roemich]

Shutter speed affects how long (or short) a duration the "shutter" is open to allow light to hit the sensor, NOT the frame rate of the camera.

A high shutter will give you a strobe-like effect (like the follow cameras on Olympic swimming).

The frame rate of your footage will be the same unless you remap the frames (60 over 24 overcrank for example) so what you are seeing you are likely stuck with.

Try adding a bit of motion blur in post, perhaps?

Good luck!

ADDENDUM: TECHNICALLY there isn't a shutter on video cameras that opens and shuts like on a stills or cinema film camera - it's an electronic equivalent that modulates how the sensor deals with the light striking it but it functions almost exactly the same for all intents and purposes...

[Daniel Browning]

Originally Posted by Mark Davis

The pictures look good on playback but make an awful stuttery conversion into Apple Prores.

I can't figure this part out. It sounds like something is going wrong with the conversion, because the stutteriness (or lack thereof) should be the same before and after.

[Mark Davis]

Thanks Shaun and Daniel.

Yes always a bit confused about frame rate and shutter speed. The effect of the high shutter speed is like some sports footage. Pretty awful look and it is important material. Not sure why Daniel, but it does play back smoothly in the camera. I was hoping there may be a way to capture every second frame in conversion to give it a smoother look. If not I will try motion blur in FCP then. Thanks Shaun. So now I am shooting in 25p with a shutter speed of 50. Is that the correct shutter speed?

And I am walking around with a pocket full of ND filters - it feels like the 70's. What is Sony thinking with this feature??

[Chuck Fishbein]

I've using a variable ND filter from Genus on mine with a 37mm to 77mm step-up ring, and I keep the shutter on manual so that it won't take off into the higher, (choppier looking) speeds. It also helps the image because smaller chips like this do not work as well with an f-stop smaller than 5.6.

This applies to all smaller chip cameras, EX1/EX3, etc.

[Mike Beckett]

Chuck,

I've been looking at getting a fader ND for my NX70. I bought the Lightcraft Workshop 37mm model and it vignettes quite badly at wider angles, so is next to useless for the NX70's 26mm lens.

Can I ask what you are using for a lens hood with the 77mm Genus?

[Mark Davis]

Didn't know about the 5.6 limitation. Thanks. Have been astounded that the cameras iris will only close down to 9.6. I guess thats why. Have been researching the variable nd filters to make this camera useable for me - otherwise was sending it to ebay. Will be receiving a Heliopan variable ND in about a week and will post results. I bought the 52mm version with step up ring. Advised that an oversized filter reduces the chance of vignetting. Not sure if that is true but will soon see.

[Chuck Fishbein]

That is absolutely true. Certainly, anything under 52mm has a chance of vignetting. The larger the filter, the less chance of getting any kind of cut-off. I'm using a 77mm variable ND. The step-up rings were under 10 bucks at B&H.

About the smaller f-stops. in my experience with the EX1 or EX3, stopping down past 5.6, will make the image just begins to go soft, the smaller the chip, the more that lens needs to be open.

[John Knight]

I've been following this thread with interest as I always thought that maintaining a standard 50(60) shutter speed is the best option.

I ordered a Variable ND filter off eBay and did some test shoots on a very bright day with manual settings of 0db, F4.0, 50ss Then I compared it to complete AUTO with no ND filter, the settings were 0db f5.6 200ss

The AUTO setting with the higher shutter speed resulted in a WWAAAYYY better picture. (Both on camera playback and on Premiere 5.5 timeline native) The ND filter made the image dull and unsharp... it was actually really bad.

I cannot see the problem with letting this camera utilise higher shutter speed in bright situations. Am I missing something?

[Daniel Browning]

Originally Posted by John Knight

I ordered a Variable ND filter off eBay and [...] made the image dull and unsharp... it was actually really bad.

Sounds like you got junk off flea-bay, a time-honored tradition that I, like many others, have long followed. However, you can also find good filters on e-bay. They are fully multicoated, not dull, not unsharp, and wont make the image really bad. You still have to use a hood, of course.

Originally Posted by John Knight

I cannot see the problem with letting this camera utilise higher shutter speed in bright situations. Am I missing something?

Did you shoot anything with movement in it? Because if you shot a still life video indoors, with nothing moving, then no-one would be able to tell the difference.

If you did shoot something moving, and you still can't tell the difference in motion blur, then it may just be that you aren't visually sensitive to that sort of thing. It's like how some people can tell when the camera is lop-sided so that the horizon is "dutch" angle, while others don't really notice. If you don't want your audience to notice that you are using an unusal amount of motion blur, then you have to stick with 180 degrees. (Personally, I absolutely hate it when cinematographers use 360-degree shutters in movies. Drives me nuts. I don't mind narrower angles very much at all, though.)

[Gary J. Walker]

I've had my NX70 for two month and been running tests every day....have to go along with John Knight...I don't have a problem using a ND filter but after running about 20 tests from all manual to fully auto (concerned with shooting with anything other than shutter at 60) I'm getting excellent results on fully auto modes...after converting to Canopus HQ files and viewing results on a 42" from 7 feet.. I'm seeing great footage from panning, fast movement (puppy running) bright sunlight (in Arizona) Iris always near 4.0 shutter between 125 (shade) to 750 and everywhere in between., image is stunning...Guess K.I.S.S. could be a good thing....Gary

[Shaun Roemich]

Originally Posted by Mark Davis

TThanks Shaun. So now I am shooting in 25p with a shutter speed of 50. Is that the correct shutter speed?

I shoot here in NTSC-land so I use 1/60 as a shutter speed for "normal" shooting of 30P, 60P and 60i material. When shooting 24P material I will make the call of 1/48 or 1/60, depending on what my light source is to avoid RGB "cycling" of fluoros...

So accordingly, in your shoes, I would USUALLY shoot 1/50 for "normal" conditions.

[R Geoff Baker]

Originally Posted by Gary J. Walker

I'm seeing great footage from panning, fast movement (puppy running) bright sunlight (in Arizona) Iris always near 4.0 shutter between 125 (shade) to 750 and everywhere in between., image is stunning...Guess K.I.S.S. could be a good thing....Gary

It's hard to know what to make of comments like this.

If you shoot with a fast shutter, anything less than 180 degrees, you generate a strobe effect on movement. You have to. The science is simple -- object is center field in one frame, and has moved towards the edge in the next; the fast shutter has it 'frozen' and crisp in both frames ... but there is a jump in location between the two frames. If the motion continues, repeat. Temporal dislocation, same as created by a strobe light.

In truth you generate this effect a little with 180 shutter too -- but most of the time it looks OK. Sometimes it looks awful -- the horrible swing scene in 'Garden of Good and Evil' comes to mind -- sometimes the strobe effect generated by a fast shutter is interesting -- 'Saving Private Ryan', though having just watched it recently I will add that the effect is modest not extreme -- but comments that don't acknowledge the look at all baffle me! You may 'like' the effect, or hate it -- but surely we aren't debating the very existence of it.

Cheers,
GB

[Mark Davis]

I received the Heliopan variable ND and all is good so far. No vignetting (52mm with step up ring). Very nice to use - like having an iris ring back on the lens. Kind of expensive but this filter makes this camera a useable proposition for me. No noticeable image degradation. If I get some sunny days I will try to post some side by side images. Thanks for help.

[Mike Beckett]

Hi Mark,

Interesting to hear this. What's your plans for a lens hood with that setup?