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Is it even worth the development effort, to use a small fraction of the 50D sensor (effectively turning 50D into a tiny sensor, consumer level camcorder), RAW or not? (I am talking about zoom RAW recording.) With a tiny sensor, you lose most of the advantages of the DSLR-based video-camera - shallow DoF and great light sensitivity.

I think Astronomiser sells the proper solution: http://www.astronomiser.co.uk/canonpowerpro.htm#ast300ddc

This is a power converter from car 12v to Canon 50D battery-type connector, for 40 pounds + shipping.

Comparable price, in French: http://www.eosforastro.com/astro-photographie/accessoires-pour-apn/adaptateur-allume-cigare-12v-pour-apn-canon-eos-details

Much pricier (but also more professionally looking) solution is Cercis A633, for 119$ _shipping:  http://www.cercisastro.com/DslrStar%20Ordering%20Info.html

Thanks - I didn't realize there were AC adapters for 50D. I spent hours calibrating my lenses, this would have been very handy. I just ordered one from ebay for only 12$ with free shipping. I do have a car booster battery, I'm pretty sure it has 12V out. Now I only need to get the inverter. 100W inverter should be sufficient, right?

It sounds the RAW hack is super battery hungry - do any of you use a battery grip for your 50D? What kind? Are there grips which provide a lot of power through AA batteries? The ones I saw take 6 AAs; with my Eneloops (2000mAh) it's only 40% more Wh than a single BP-511 battery, doesn't look interesting. Are there grips which would have triple or more the Whs of BP-511? I never had a need for grip, with my 3 batteries, but now with the video feature I might reconsider.

Going back to my question of a beep at the video recording start - I really hope it will materialize. I just received my Zoom H1 recorder - really cool stuff! It'd be great to have a convenient way to sync its audio with the 50D video.

Could anyone please give me a link to the description of how RAW is done under Magic Lantern?

Specifically, it is not clear to me what is the 14 bit color. My understanding is that for some video modes the whole sensor is used. The sensor itself is 14 bit per pixel + Bayer matrix to get proper colors by interpolation. To make 1080p video from the whole sensor, one has to bin multiple pixels. What is binned by ML - the raw pixel values (before demosaicing)? Perhaps separately for the pixels of each color (R/G/B)? And what is the RAW video format: is it 14 bit per pixel, and has to be demosaiced? Meaning the color resolution is pretty poor?

Thanks.

I was probably confused by the statement from 1% on page 50:

Audio stuff is all in there.. mic is not hooked up.. audio is ak4646. I was going to make it beep next... but battery died. i'll have to use AA's.

So does 50D have ak4646? Form the chip description:

The AK4646 features a stereo CODEC with a built-in Microphone-Amplifier and Speaker-Amplifier. Input circuits include a Microphone-Amplifier and an ALC (Auto Level Control) circuit, and Output circuits include a Speaker-Amplifier.

Anyone tried Kingston Ultimate 600x 32GB ? The claim is it is 90MB/s write speed, the real life performance is more like 76 MB/s (http://www.gavtrain.com/?p=1831). I wonder how does it fair on 50D? It is on sale now here in Canada (Canada Computers, 60$).


Also - any more information regarding audio support in 50D on a hardware level? I saw it discussed here on page 50, with the statement that 50D seems to have the audio chip. If there is a way to simply solder in an audio in connector (to be used e.g. with Zoom H1 recorder) that would be super sweet.

So it does seem to me possible?

I've just noticed that on ML wiki guide, the optional beep at the start and end of video recording is possible, but I don't see this option on my yesterday's nightly binary ran on my 50D. Does it mean that this option isn't enabled only on 50D? Why - is the beeping part of 50D different from other cameras?

I have just ordered an external audio recorder (Zoom H1), and for the first time will seriously look into the ML's video option on my 50D. I suspect the biggest problem will be to achieve good audio sync. It occurred to me that perhaps ML can implement a new feature which would once and for all fix this issue for 50D videographers: make the camera emit a loud and short beep when the video recording button is pressed on the camera - ideally with the ability to fine-tune the delay between the video start and the beep. Then the sync could be easily achieved in video editing software, by matching the peak on audio waveform with the start of the clip.

Is it possible?

Thanks!

Another solution for the same problem - perhaps it is easier to implement? Instead of remapping any buttons, a new feature 'delayed LiveView AF' would achieve the same thing. Specifically, if there were a ML option which would introduce a delay between the moment the AF-ON button is pressed and LiveView AF action then one could achieve very accurate contrast detect AF even with telephoto lenses (no camera shaking). For this to work, the AF would have to run on its own (not as long as AF-ON is pressed, as it is now), until perfect focus is achieved, or until it times out.

I always found it very annoying that the most accurate (albeit slow) way to focus on my 50D  - using LiveView AF - can only be engaged by pressing the AF-ON button at the back of the camera. This pretty much fails when you try to do it with either long telephoto lenses (>100mm) or using macro lenses - even with a sturdy tripod, the camera shakes so much when you are pressing the AF-ON button that the focus is often not accurate. E.g., when using the new feature of Magic Lantern - dot-tune lens calibration - the very crucial first step (putting lens in exact focus) - fails for me with my 135mm and 200mm lenses, because of too much shaking.

Ideally, I'd like to be able to trigger LiveView AF using my remote shutter control, but it only works with the phase-detect AF, not with Live View AF. Apparently, many Canon cameras suffer from this deficiency: http://www.dpreview.com/forums/thread/3093770 . For 50D at least there is one option - to tether camera to a laptop with Canon remote shooting software (but that defeats the purpose for using ML), but apparently even this option is not available for other cameras (Rebels).

Is it possible for ML to map AF-ON button to the half-press shutter button? That would make it possible to do LiveView AF using remote shutter control.

[and]

Thanks - I am also experimenting with this right now.

Actually, one simple ML modification would accomplish most of what I'm asking for: if at the end of calibration ML would print on the screen not just the median value, but the good interval as well. Then one can do any kind of calculations with these numbers.

I know the good interval is a function of the distance - but so is the median MA value as well, for many lenses. As a result, MA calibration is normally done at the typical distances the lens is used, hence the good interval information should still be valid.

The essence of my original point is that not just the median, but the whole MA interval information is valuable, and should not be discarded. The whole interval corresponds to MA values deemed "as good as it gets" by the AF system of the camera (or at the very least as "sufficiently good"). I'd expect this interval being wider at shortest FL of zoom lens (because of deeper DoF), and more narrow at the longer end (more shallow DoF). Using my approach to find the optimal MA value would take this DoF behaviour into account, and allow you to find the MA value where AF deviation from the perfect focus is comparable (in DoF units) at any focal length.

Here is actually another possibility - even more accurate way to find the optimal MA for a zoom which has different MA and different interval widths at the opposite FL ends perhaps would be to assume the interval width (or rather half-width) as a std (standard deviation), and the compute the optimal MA as a weighted average, using the standard formula:

<MA> = [MA1/(del1**2) + MA2/(del2**2)] / [1/del1**2 + 1/del2**2].

All these different approaches can be tested, if only ML could print the good MA range at the end of calibration.

No, I am not talking about means, I am talking about overlapping intervals, these are different things. In the case of say [-16...0] at one FL end and [-2...+2] at the other, the cumulative approach would yield MA=-1. The mean of means would yield MA=-4 - definitely bad number, as it is outside of the good MA values for the second FL.

So, no comments about my "cumulative mode" suggestion (see two posts above)? It wouldn't be too hard to implement (I think), and zoom lens owners would really appreciate it.

I have another suggestion for dot-tune improvement. How about an optional 'cumulative' mode? Specifically, when testing zoom lenses or/and lenses at different distances from the target, one often gets different good dot-tune intervals for MA. E.g, my Sigma 17-50  has MA say -15...-2 at 17mm, and -5...+5 at 50mm. The current dot-tune implementation is not very useful for finding a single compromise value for MA which would be acceptable at any FL. All I get is either one FL or the other FL values; the important interval width information is discarded. But if ML had a cumulative mode, and let me run dot-tune a few times at different FL, and then computed a single compromise value taking into account interval widths, that would be very helpful. In my example, the common MA interval for both FL is -5...-2; the compromise value would be either -4 or -3. At the very least, you could make ML print out the intreval at the end of every calibration; the compromise value would be computed manually.

Either way, that would be an improvement. More power to users is always a good thing!

Thanks for the detailed response! But this begs a suggestion - would it be possible to let the user choose both the number of passes and the duration of one measurement, from the ML menu?

Thanks - but wouldn't lower weight be reflected in shorter bars in the MFA progress diagram? When I get less-than-good AF confirmation, I can still see the bar having the same height as for good MFA values.

I just did fairly comprehensive testing of dot-tune/ML on my 50D, using  magiclantern-v2.3.NEXT.2013Mar02.60D.550D.600D.50D.500D.5D2.1100D.zip. The results are reported here:

http://photography-on-the.net/forum/showthread.php?t=1280584

In particular,

- ML implementation of dot-tune is not perfect yet - at the edges of the good interval, I could see the delay in AF confirm light, sometimes double beep (all these should be discarded according to the Dot-tune author, but ML would apparently still consider them okay, and count them in). Meaning - you can do slightly better if instead of using ML, just do dot-tune manually. But I am sure this will be addressed quickly in the future releases of ML.

Thanks for the efforts - fantastic project! I just wish one day you will figure out how to make MFA values FL and/or distance dependent.

I gave a try to the nightly built on my 50D, and happy to report that it seems to be working fine. I will do more thorough testing with good light and target, comparing ML/dot-tune results to FoCal results, on my fast lenses (135mm f2.0, 17-50mm f2.8, 70-200mm f4).