To Rick Burnett.

[George D.]

Thank you Rick Burnett.

Finally someone without a problem, a hang up, or misguided loyalties.

How am I supposed to know what everyone else has asked? I don't spend every waking moment on the RED Forum looking at other peoples questions. If others are too tired to answer a question, don't answer it.

Rick, will you kindly explain to me what "line skipping" is? And, any other thing you feel is detrimental to shooting professional video for TV with DSLRs?

If you don't have the time, would you please give me a source where I may find out this information?

Thanks much for your compassion, consideration, and time.

 

[Martin Weiss]

George,

For private messages it is best to use the PM function.

Other than that I would suggest naming your thread title in a way that makes it quick to understand what your post is about, otherwise you'll lose a lot of potential input from users who happen to have a name other than Rick Burnett.

When asking general questions, it is always a good idea to spend a few minutes on trying to finding out yourself. If you don't find anything, say so - otherwise some users will assume that you didn't bother to do any research and will scold you for that. Just basic netiquette. Just like any internet forum, people like to be helpful - but dislike being asked the same question again and again by different people.

Line skipping generally refers to a technique for downsampling (i.e. making smaller) images. On many DSLR cameras, the sensor has way more pixels than necessary for video output. You would achieve the best result by reading every single pixel and then downsizing the image in the camera to the required size. This takes a lot of processing power, and many cameras do not have this. So they employ a different technique, where not every line is read (i.e. "skipped"), something which will cause all sorts of visual problems down the line, e.g. moire and "fuzzy" lines.

I'm sure there are others who can give much better explanations.

 

[Rick Burnett]

Wow, I have a thread named after me!

George, no problem at all. Many line skipping cameras throw away almost 90% of the sensor data when capturing video. This could be due to how slow the sensor is at reading out that information, or other parts of the design where the storage or compression mediums cannot keep up with higher data rates. For instance, on my DSLR, for full frame images it does a max of 8 frames per second. Clearly 4 times slower than 24p.

It is of my opinion that the reason they do this is because the cost to make that camera fast enough to do full screen captures is just too cost prohibitive for the market segment they are capturing.

So, what does that mean?

Well lets look at a common example. On the 7D they skip two out of every three lines. That means that the active area where data is being recording is almost 1/3rd. 2/3 of the image coming in is not used AT ALL. Now look at it in the vertical direction because tests have shown they throw out pixels in the row as well and you loose another 2/3 of the image hitting the sensor. That means you are getting 1/3*1/3 or 1/9th of the information.

Sine the optical low pass filter over the sensor is designed for the full resolution, spatially high contrast information hits the sensor and means that fine detail is lost in those areas where the sensor data is ignored. I'll even go so far to say that with a proper OLPF on this sensor it would look like complete crap because there is so much dead space between the active pixels. OLPF work best when then dead area around pixels is much lower in magnitude than the active area (basically an OLPF spreads an image between adjacent pixels, blurs or copies, so that that detail is made large so it is not lost between the pixels).

In your recorded results, this comes out as moire patterns and aliasing. Both of these are REALLY bad at 1080p line skipped 12Mbit sensors, and even MUCH WORSE at 720p.

This means that any sort of deep focus shots, or really focused shots on fabrics and patterns get HORRIBLE artifacts in them. And when I say horrible, that is an understatement. It's worse on Canon cameras because it's all rainbowed with color.

This is why getting a camera that does not line skip and has a proper OLPF is essential if you want to not limit yourself in what subject matter you can shoot.

 

[George D.]

Man, YOU are one nice guy, and I really appreciate all the trouble you went to to type all that up for me. Too bad some of the other users of this forum aren't the quality you are.

You are one smart, knowledgeable guy. I understand now. Thanks to you, I also was able to look some stuff up on the internet like you suggested, and found this:

http://poetzerofilm.com/2010/04/8-reasons-not-to-buy-a-dslr/

Your info and that article did it, and completely convinced me that DSLRs are NOT the way to go. The footage we shoot is too hard to get in the first place to risk any of it not being usable for "any" reason. Money is secondary.

We'll wait for the Scarlet, or maybe even a Red-One.

Thanks again for your kindness.

Be well, and have a great life. Much success to you.

 

[Rick Burnett]

I'd go so far to say that in the area I live, I've really spear-headed the in depth analysis of at least the 5D and 7D cameras. That article is VERY well written in terms of what the major issues are with these cameras. I think ANYONE wanting a DSLR should read that, thanks for pointing it out, as I am going to pass it along.

That is not to say you cannot get nice quality out of a DSLR, it comes at a huge cost.

Also, the people around here are typically very supportive. Only recently has there been a rash of camera bashing I think out of frustration in the industry at the moment. I can see valid points from all sides, but don't let that scare you away. I mean, I am still here I have learned SO MUCH from this user group and am very glad to be a part of it.

While a Red One for me would be fun, I'd wait for the Scarlet or Epic if you were considering a DSLR. For me, it's the form factor alone. I know it can be frustrating to wait, I've got the money for my Scarlet Fixed in the bank right now waiting to be spent, but in the end, from the insight I have gleamed from this board and the posts of Red employess, I think the wait will be WELL WELL worth it.

 

[Raul Gonzo]

Hey George- there are really a lot of nice people on this thread.
It's just that a lot of the same questions get asked over and over- and it sounds like a broken record in the jukebox when actually it's just different people stopping in and playing the same song.
Where in NorCal are you?

 

[George D.]

Thanks again, and again Rick.

Hi Raul,

I live way up in Humboldt County, in among the Redwoods. Love it here.

I appreciate your input on the people frequenting this forum, and I'm sure you're right. I just don't understand rudeness and impolite responses. We are all on the same planet after all.

I am VERY knowledgeable on film, being a professional of over 36 years, but digital video, like the Scarlet and Red-One are brand new to me. Nevertheless, I have every intention of capitalizing on their assets.

 

[Raul Gonzo]

Humboldt is beautiful- I,ve been up there a few times and didn,t want to leave.
I live north of Sacramento - so I just wondered how close you were.
Well- I encourage you to continue to ask questions- just do what I do:

First I'll use the search engine here on red (or actually, I get better results putting in keywords in google and then "reduser.net")

If that fails I,ll start a new thread and see where that gets me.

Otherwise you can PM me or (probably) Rick if you want.

 

[George D.]

Thanks again, and will do.

Have a good one.

Bye for now.