How do DSLRs shoot video? - Page 1
Forum section: electronics / general

author: clickcell
author_rank: Contributor
timestamp: April 12, 2014, 02:24:46 pm
content: So some camera buffs got shirty with me and said a DSLR can never work without a shutter and I hurt their feelings by even suggesting it... so how do they shoot video then? Pretty sure I don't hear the shutter going 60 times a second or whatever.

author: cyr
author_rank: Frequent Contributor
timestamp: April 12, 2014, 02:37:17 pm
content: Simple, the "buffs" don't know what they are talking about.Modern DSLRs can work without using a (mechanical) shutter, or they wouldn't have live-view or video modes. I think mechanical shutters are still used to take still photos because blocking the light from the sensor prevents blooming and other artifacts which you can get when using only the electronic "shutter" built into the sensor.

author: Tinkerer
author_rank: Frequent Contributor
timestamp: April 12, 2014, 02:42:34 pm
content: Maybe you should ask them how they think think normal video cameras work. Both of these work basically the same way.

author: NiHaoMike
author_rank: Super Contributor
timestamp: April 12, 2014, 07:03:27 pm
content: There are even a few video-oriented "compact DSLRs" that dispense with the mirror optics (and in some, the mechanical shutter) altogether.I wonder when there'll be an affordable DSLR (either conventional or compact) that can do 4K.

author: Marco
author_rank: Super Contributor
timestamp: April 12, 2014, 10:03:28 pm
content: DSLRs can obviously work without a mechanical shutter, but they can't be DSLRs without a reflex mirror ... it's in the name.In video mode the reflex mirror isn't used, so you have to use the LCD (which is why there are addons for HDSLRs, which have optics to let you use the LCD more like the standard viewfinder).

author: NiHaoMike
author_rank: Super Contributor
timestamp: April 12, 2014, 10:20:57 pm
content: They could use a partially silvered mirror, although that would limit low light and fast exposure performance when the optical viewfinder is in use.The "compact DSLRs" are called that because they have swappable lenses just like conventional DSLRs. Kinda like a SSD being called as such even though there are no disks inside it.

author: pickle9000
author_rank: Super Contributor
timestamp: April 12, 2014, 11:02:13 pm
content: There are a couple issues with dslr's and video.- The first it that the mirror takes up space and prevents some lenses from being used. Having said that compared to a purpose built consumer camera the selection is far superior so in that respect it a plus.- The second is a lack of a shutter. It's an issue even with a camera such as the Red Epic, in that case a third party came up with a solution by making a lcd shutter and it actually works.I think in general dslr's that can do video are better mainly because of the lens selection. Canon and certain Lumix (not actually a dslr) can produce very good video. As for the lack of a shutter, it's an issue but up to the creativity of the filmmaker to use the equipment to it's fullest.

author: pickle9000
author_rank: Super Contributor
timestamp: April 12, 2014, 11:07:53 pm
content: Here is a sample for you to look at. A non-professional Panasonic GH2 with a brushless gimbal.

author: theatrus
author_rank: Frequent Contributor
timestamp: April 12, 2014, 11:28:26 pm
content: A mechanical shutter is still required to end the exposure reliably on a DSLR. Most sensors incorporate an electronic "first curtain " blanking signal.Video on most sensors is done with a continuous rolling readout. On cheap sensors the scanning readout shows as a very pronounced "jelly" effect when moving. Even higher end units with rolling shutters (all? Dslrs) will show it.Sent from my iPhone using Tapatalk

author: pickle9000
author_rank: Super Contributor
timestamp: April 13, 2014, 12:15:31 am
content: The jello effect is common but not as big a deal as many make it out to be. Here is a video showing the effect, one of the cameras in the video are the same as the one used in my previous post.Yes it's an issue but I'd still say that the skill of the person taking the video is of more importance.Give me a 100,00 dollar camera and George Lucas a dslr and I will still make a steaming pile of crap. George Lucas may come up with the most watched wedding video of all time.

author: sacherjj
author_rank: Frequent Contributor
timestamp: April 13, 2014, 01:06:06 am
content: Quote from: pickle9000 on April 13, 2014, 12:15:31 amUnless it is a wedding involving JarJar...

author: pickle9000
author_rank: Super Contributor
timestamp: April 13, 2014, 01:14:58 am
content: Quote from: sacherjj on April 13, 2014, 01:06:06 amOK, I can't argue that one.

author: Someone
author_rank: Super Contributor
timestamp: April 13, 2014, 01:32:28 am
content: Quote from: NiHaoMike on April 12, 2014, 07:03:27 pmThe current entry level for 4k:http://nofilmschool.com/2014/04/panasonic-4k-gh4-camera-yagh-xlr-nab-2014-hd-sdi/orhttp://www.cnet.com/products/sony-handycam-fdr-ax100/

author: pickle9000
author_rank: Super Contributor
timestamp: April 13, 2014, 02:02:06 am
content: Wow, that gh4 is nice, not to mention the operator.

author: pickle9000
author_rank: Super Contributor
timestamp: April 13, 2014, 05:32:18 am
content: That Jacques-Henri Lartigue pic is really neat. Knowing your equipment is so important.There is one other issue with dslr's and that is the focus system while taking video. A pro will often use a "follow focus" rig. That is the focus will be done by a helper and often worked out in advance. Rigs for dslr's are available but it would be nice to have a more advanced system for a dslr.

author: pickle9000
author_rank: Super Contributor
timestamp: April 13, 2014, 07:07:32 am
content: Here is a group or semi-professionals? I'm not really sure but "Film Riot" certainly do a wide variety of stuff. The link below are is a best of set. Of interest here the first segment was done on an i-phone most of what they do is on a Canon 5d and a couple Canon lenses.There has been talk on the show about 4k but mainly that is so they have more control in post processing. If you output at 1080 then the 4 k allows for scene adjustments, image stabilization stuff and such. It's fun to watch at any rate.

author: Legion
author_rank: Frequent Contributor
timestamp: April 13, 2014, 02:09:27 pm
content: Quote from: theatrus on April 12, 2014, 11:28:26 pmI've always wondered why, from a technical standpoint, CMOS sensors use a rolling shutter? Is it impossible, or just economically unfeasible to read all the lines in parallel? CCD sensors didn't have the rolling shutter problem, but from what I've read they became prohibitively expensive to produce at larger sensor sizes.

author: NiHaoMike
author_rank: Super Contributor
timestamp: April 14, 2014, 03:03:09 am
content: Quote from: Legion on April 13, 2014, 02:09:27 pmThe issue is the sheer bandwidth requirement. It's already hard enough with 4K, now try to get that out in the blanking interval...Note that the tube cameras first used in electronic video capture effectively have "rolling shutters" as well.

author: pickle9000
author_rank: Super Contributor
timestamp: April 14, 2014, 03:24:41 am
content: Here is a good article on shutters, note it's onhttp://www.red.com/super expensive digital video cameras for the movie industry. The article is directed at movie professionals, so it is easy to understand.http://www.red.com/learn/red-101/global-rolling-shutterThe cameras are interesting and worth looking at.I wonder if they purchased the .com name? If they did it must have cost a fortune.