Two camera technology ideas for you to pick apart

[Phil Douglas]

I've had a couple of camera tech ideas over the last few days - would they work? Or has something similar to these already been done?


Idea 1: Using 2 or more sensors to expand dynamic range.

Could you not split the light coming through the lens and send it to two sensors within the camera (using a prism - though i am guessing you may lose a stop or more doing this), and then increase the gain on one of the sensors by 5 (as an example) stops above the other - (so that now one of the sensors is over-exposing the image by 2 1/2 - 3 stops and the other is under-exposing it by a similar amount), then using an algorithm within the camera, stitch the two images from the sensors back together and record it - in essence giving you 5 more stops of exposure to work with.

The number of stops you would be able to shift (bracket) between the two sensors would depend on the dynamic range of the sensor(s) being used. Also using even more sensors could expand the dynamic range further (along with the cost of the camera).




Idea 2: Auto Rack Focus

I am currently using a C300 which will apparently get some type of auto focus feature in the future - and this idea would only work with cameras that have control over focus.

It would be nice if I could access an "auto rack focus" (ARF) feature within the camera that would allow me to manually (or auto) focus on subject A - push the ARF button to set this 1st focus point - then refocus on subject B - push the ARF button again to set this second focus point - at this time the camera would ask you to set the ARF time - I am going to adjust it to 1.5 seconds for this shot. Then i would hit the ARF button one last time and the camera would set the focus back at the first point (which I could double check through the EVF) and I would be ready to go. Now I am ready for the take and I would hit record - and knowing that the rack will take exactly 1.5 seconds to complete, during my shot I would push the ARF button at the moment when I wanted the rack focus to begin.

If the above is possible, this would allow me at times when i am a one man crew, (no focus puller etc), to pull off a nice rack focus using still camera lenses with relative ease.

Please let me know what you think.
Phil

[Mike Beckett]

My old Sony V1E HDV camcorder had the second feature, you could program two focus points (or other effects) and smoothly transition between them. It was magic. I wish all camcorders had that!

[Warren Kawamoto]

I'm just guessing, but doubling your sensors will also increase the number of electronic components required, and probably double the power consumption and heat. Mike is right, Sony cameras from Z1 and up usually have programmable focus points which makes pulling or effects a breeze.

[Ron Evans]

The Sony FX1 had the second feature and the present EA50 has this too with control over the timing as well. Lots of consumer cameras have touch spot focus but normally it is at a fixed timing.

Ron Evans

[Phil Douglas]

Originally Posted by Ron Evans

The Sony FX1 had the second feature and the present EA50 has this too with control over the timing as well. Lots of consumer cameras have touch spot focus but normally it is at a fixed timing.

Ron Evans

Is Sony the only manufacturer that has this feature (ability to pre-set multiple focus points) on their cameras?

I've used cameras with the touch focus and it can be very useful - if i recall correctly i think that is a feature that they will be adding to the C300 in a future firmware update.

[Pete Bauer]

Originally Posted by Phil Douglas

Is Sony the only manufacturer that has this feature (ability to pre-set multiple focus points) on their cameras?

Canon XL and XH cameras have one focus preset but they dropped this feature from the XF line. The XF has a Push AF, but that's not the same as being able to preset a particular focus. I don't own an EOS Digital Cinema professional camera, so maybe someone who does can chime in, but looks like a focus preset capability is more dependent on which lens you use than the camera itself.

[Seth Bloombaum]

Originally Posted by Phil Douglas

...Idea 1: Using 2 or more sensors to expand dynamic range.

...then using an algorithm within the camera, stitch the two images from the sensors back together and record it - in essence giving you 5 more stops of exposure to work with...

I don't think we have an algorithm for this to run automatically at 60/second. If you look into the various tools for High Dynamic Range (HDR) photography, you'll find that shooters are making decisions in post about how to map their 20 or more stops of dynamic range to an image for viewing.

There are artistic choices to be made. To my eye, some HDR looks plasticy, as if generated by a 3D program. We've learned to look at video and film in which, at the extremes, blacks are crushed and highlights blown out; it's part of the visual language of film. The plastic/3D look of some HDR is due to an abundance of mid-tones where we don't expect them.

It could be done, perhaps with more control given to the shooter, something like black - mid - white controls and good monitoring... ?

Magic Lantern for EOS cams has an interesting approach to HDR for video I've not yet tried; it will let you shoot different exposures on alternating frames. Then you run a script in post to demux them, and you can merge the two streams in an NLE. Or something.

But I do think it has potential in that correction is a post process...

*******************************************************
You gotta' look at this autofocus demo for the new Canon 70D. I think it shows the future of what we can expect from AF - touch-screen selection of focus point. This is the first video AF that looks really promising, in that it allows the shooter to choose, on the fly...

In particular, check out the rack focus (touch autofocus) at :26, then the behind the scenes look at lensing at 3:24. I am an official old-fart we-don't-need-no-stinkin'-auto-anything curmudgeon, but I am excited about what touch autofocus makes possible.

Handmade - Canon EOS 70D (First Look) - YouTube

[Dave Blackhurst]

As noted, the preprogrammed focus has been available for some time, and touchscreen focus is fairly common and reasonably effective.

And some Sony cameras (and IIRC a Sony cellphone imaging module) have some form of "HDR" - sometimes referred to as "DRO" or Dynamic Range Optimisation" that allows a shooter to adjust the way the image is processed to allow more or less dynamic range. I know it's rather effective in the RX100 (compact camera shooting 60p full HD).

[Phil Douglas]

Seth - thanks for posting that video, it's about time autofocus became a useful tool for video - i think that i would rather have this feature at my disposal than the ability to set multiple focus points that i mentioned earlier. I hope this makes its way to other models/manufactures products and is not just a novelty for the 70D. And for the most part I agree with your views on HDR photography, it can look quite stunning as an effect - but like over saturating colours in an image, it ends up looking not quite real.

Also- I have checked out Magic Lantern, and it is awesome, though not really for me as I don't shoot a lot of video with DSLR's.

On the same topic of focusing - are people on this site aware of the Lytro cameras? Where you focus images after they have been shot. If not you should check it out - it is quite interesting. [Edit -- I did a quick search and see it has been discussed on this forum]

[Steve Game]

Just for the record, Sony call it 'Shot Transition' where the start and finish settings can include focus, iris, gain, shutter speed, white balance and zoom. The transition duration and start/finish curves can also be set individually.
The programmed zoom transition makes consistent effects like a 'dolly zoom' possible.
Its a shame that the feature doesn't seem to be offered on current models.

[David Heath]

Originally Posted by Phil Douglas

On the same topic of focusing - are people on this site aware of the Lytro cameras? Where you focus images after they have been shot. If not you should check it out - it is quite interesting. [Edit -- I did a quick search and see it has been discussed on this forum]

For anyone who didn't see the initial threads, then "interesting" is quite a good description! On the plus side, it does give the unique facility of being able to refocus the image (to an extent) after taking the image.

On the negative side, that feature comes very much at the expense of resolution of the final image. So much so that the camera can't really be considered acceptable by todays standards for normal photography - it relates to a final square image of about 1 megapixel, and even that comes at the expense of making the refocusing between planes of focus somewhat coarse.

The underlying technology is not new, and used quietly for quite a while in industrial products - where trading resolution for depth information can be highly useful in specialist applications. (See Applications - Raytrix GmbH for examples of applications.) Lytro were the first (?) company to try to market it as a consumer product, and now their product has been out for a while it seems that whilst it fundamentally works as claimed, it has various issues (including the price!) which make it unattractive to most users compared to a conventional camera. That shouldn't be unexpected.

[Chris Harding]

Hi Guys

Sony's new EA-50 has the rack focus feature as well..you can preset two points and also specify the timing between the two to produce a seemingly perfect focus shift. I personally haven't used it at weddings as I normally have my hands full but it would work well on a controlled shoot if you had plenty of time.

Not sure if the big brothers (FS100 and FS700) have the feature though.

Chris