Messages

151

Hardware and Accessories / Re: Ballhead/Hotshoe for 7" tablet

« on: August 31, 2012, 08:50:44 AM »

I cant help with your mounting issue, but how do you plan to get the image from the camera onto the tablet?

It sucks that there arent any cheap tablets etc with an HDMI input, would be such a perfect solution to having a decent sized live view monitor without breaking the bank.

152

General Help Q&A / Re: Bitrate increasing

« on: August 31, 2012, 08:46:47 AM »

It still seems unclear to me as to whether there's any point in getting a 95mb/s card, as your camera needs to put the card into UHS-I mode to run at that speed - which only a 650D can do as best I can tell, which doesnt have magic lantern available for it yet.

One thing to try that seems to help though, turn off the magic lantern overlays, so its a clear view on the display, and turn off the audio.

I've been able to record at (up to) 1.8x the bitrate with no stops doing it that way.

153

Hardware and Accessories / Re: DIY camera rig / matte box etc

« on: August 31, 2012, 01:54:32 AM »

Yeah plastic blocks etc would work really well... While at a 'prototype' sort of stage where I'm not sure what I'm going to prefer, having a material that's easy to work with is priority over absolute lightness or appearance.

So might be a few revisions yet, and a bit more work on the follow focus setup.

Once I've got a design I like I'll likely make the crossmember parts from U shaped aluminium extrusion, so the frame will be as light as is practical to do with reasonably cheap materials.

154

Hardware and Accessories / DIY camera rig / matte box etc

« on: August 30, 2012, 01:20:39 PM »

Hey guys,

Given that I've got a limited budget for camera gear (who doesnt) to me it makes sense to pay $$$ for the things I cant make myself (like fancy lenses/glass) and not spend $$$ on things I can probably hobble together myself.

Had the day off work today, so thought I'd put together a basic camera rig to help with my otherwise parkinsons-esque shakeycam shots.

Consists of:

-Some wood and 12mm ali rod from the local hardware store as crossmembers/runners
-a plastic lunchbox for the base of a matte box (need to build shades yet)
-a smaller plastic box for a matte box for the liveview screen
-12mm rod with a ground down nut bashed into the end, + some hoseclamps that they wind onto as a basic follow focus
-Aluminium U section to attach to the tripod.
-A can of matte black paint

Apologies for the bad pics, lense was stuck on F1.8.









Will spray the whole thing matte black when more or less finished, so it passes the '10 meter rule' for not looking ghetto 

I cut and drilled about 6 of the wooden crossmembers, so if I think of other stuff that might be useful to add later its all modular.
I can take bits off and add bits on to make it a shoulder mounted rig, or on tripod, etc.
So still a few more bits to do before it'll be useful for much.

Even so, it's cost me about $40 worth of materials so far, vs an equivilent off the shelf rig that costs $450 or so here.

Need to practice focus pulls, it isnt easy!
I've got a good idea for making some stoppers for the focus 'arms' though, will see how that goes...

Anyone else here made anything DIY for a camera setup?

155

General Help Q&A / Re: SanDisk SDHC 45MB/s or 95MB/s, is more speed worth it?

« on: August 20, 2012, 01:15:44 PM »

Are you saying that the 4gig limit is no longer present?

Or that the 30 minute limit is no longer present?

Great news either way if so!

I would assume the 4gig limit is still there, since the "video remaining" counter has the option to display how much of 4gb is left?

156

General Help Q&A / Re: SanDisk SDHC 45MB/s or 95MB/s, is more speed worth it?

« on: August 18, 2012, 03:03:56 PM »

Hey thanks, yes you raise some good points.

However since we have a 4gig limit per video file, the bitrate tradeoff becomes a bit more complex.

If I buy a 128gb card, it doesnt mean I can record at 3x bitrate for as long as a card 1/3rd the size with normal bitrate.

I certainly agree that generally speaking recording at a higher bitrate is better, but for some shots of mine I'll likely be downsizing mine from the factory bitrate to acheive a longer record time within 4gigs.

Even without the 4gig limit it's diminishing gains for recording at a higher bitrate in terms of perceivable quality.

However with the size limit issue you were recording at 100mb per second, being able to record for only ~40 seconds at a time is very impractical.

Regarding the 95mb/s cards, I've been doing a bit of homework into this. From what I can gather the 95mb/s Sandisk cards can only write at that speed when they are in UHS-I mode.

The 600D doesnt support UHS-I mode, it requires running the card at a lower voltage to usual.
So the card is only run in the 'normal' mode at a higher voltage, however fast that may be.
Not sure what this means in terms of how fast it would actually write, I would be interested to see a back to back comparison between the 45mb sandisk card and the 95mb one on a non UHS-I device like the 600D.

I'm looking at purchasing a 32/64/128gb card, and I'd be willing to spend the $$$ on a 95mb/s card if I saw proof of if it's actually capable of being utilised.... And I wouldnt want to  commit to a 45mb/s if a 95mb card could be used above the capability of a 45.

I'd love to see the difference quantified between the 45 and the 95 on the 600D or similar, but I might have to just take a punt on that one.

157

General Help Q&A / Re: SanDisk SDHC 45MB/s or 95MB/s, is more speed worth it?

« on: August 15, 2012, 02:54:45 PM »

Where are you videos going to end up?

If on Youtube or Vimeo, your bitrate gets slaughtered anyway so I cant see much advantage to cranking up the bitrate.

And it gets a bit silly if you can only film a few minutes of footage on a 64gig card, both at the time and editing afterwards.

Here's a quick graph I made of audio/video bitrate of what I'm able to record, vs the maximum of how it ends up online:




You can see that even a cheap camera like a ContourHD or a GoproHD is well capable of blowing out the Youtube bitrate... But audio can (potentially) be uploaded at a comparatively better quality with the Canon.

158

General Help Q&A / Re: My filming goals, Bitrate vs framerate vs compression? (tl;dr warning)

« on: August 11, 2012, 10:53:40 AM »

Yep, although cmos wobble is an issue with the rolling shutter, based on some thoroughly unscientific testing it apprears  to be a lot less an issue than with other HD cameras I've played with. (like gopro / contourhd)

Presumably because the 600D scans each line at a quicker rate / more processing power?

Does minimising the shutter speed help with that issue at all?

I've done a few in car tests with it (just street driving though) and no noticable CMOS wobble.

The webcam that I've got connected gets it horribly, which is why I'll have it pointed at something relatively stationary. (Like the foot pedals)

159

General Help Q&A / Re: My filming goals, Bitrate vs framerate vs compression? (tl;dr warning)

« on: August 09, 2012, 09:57:12 AM »

Okay thanks.

I thought you could adjust the framerate with magic lantern, independant of what the original options were now?

Or does that mean 60fps changed to 24fps in ML will play back as fast forward? (Havent tried yet)

160

General Help Q&A / Re: My filming goals, Bitrate vs framerate vs compression? (tl;dr warning)

« on: August 09, 2012, 09:37:44 AM »

One other question, since the audio portion presumably consumes part of the available video bitrate, would disabling sound where not required, give a better quality picture also?

(Theoretically at least... my filming skills are likely the bottleneck for now!)

161

General Help Q&A / My filming goals, Bitrate vs framerate vs compression? (tl;dr warning)

« on: August 09, 2012, 09:18:10 AM »

Hey guys,

First of all I'd just like to say that if not for Magic Lantern, I'd have not bought a DSLR.

I had in mind that if I was going to spend $$$$ (comparatively) on a camera, it would need a minimum amount of features such as timelapse, which none seem to have out of the box... Found Magic Lantern, bought a 600D and life has been grand 

Okay, so one thing that I want to acheive this year, is to make a good quality video about taking my racecar to the track, racing around, the social side of it, etc. As well as a timelapse or two and a few of Magic Lanterns other fun features.

My plan so far is to record with:

600D with 8mm Samyang fisheye lense, stereo shotgun mic.
This will be mounted in the car looking out the windscreen / view of driver, will record at 720p 60fps.

Netbook with a 20hz GPS receiver and software, a webcam connected recording at 640x480 30fps for a picture in picture view of perhaps the pedals/drivers feet.
The audio portion of the webcam video will be with a Blue Yeti USB mic in a secondary position to capture engine noise, or exhaust noise or whatever.

A Contour HD modified to recieve an external mic input, this could possibly use the headphones output of the Yeti mic as the input, or put the shotgun mic on this and use the standard Canon audio.

So I'm pretty much sorted for what I want to do with the above I guess, but there are some other segments I am planning to shoot where I am torn between aiming for 1080p or 720p.

Since there's a maximum bitrate for the camera (is this before or after compression?) is there any picture quality to be gained by shooting at say 720p 24fps over 1080p 24fps? Would less colour detail etc get compressed down by the codec, if more data can be allocated to each frame? Or is it not likely to make a difference?

Since some portion of the video will be 720p anyway to get 60fps, I figure I'll aim for this for the rest, if it's a case of post codec quality advantage vs pixel count.

If anyone can help, or perhaps has any hints or tips for shooting in car / out of car automotive stuff, I would greatly appreciate it