Digital Extender vs. Optical Extender
 

Recently on another thread there was a discussion about the quality of Sony's "Digital Extender" function. This function can be activated at the touch of a button to magnify the recorded image by 2x. It is rumored this will be added to the PMW-350 and/or PMW-320 later this year via a firmware update.

The PDW-F800 has this function already and I thought some people on this forum might be interested in how good it might be when it is released. So I thought I'd do some side-by-side testing to see how Digital Extender compares to the optical extender of my Fujinon ZA22x7.6 lens.

My goal was to come to my own conclusions once and for all if one of them is better than the other. And if so, which one? In theory the optical extender should be better. But even if that is true, is the several thousand dollar extra cost to get a lens with an extender vs. the same lens without an extender, worth it? And what about light loss? Even if the optical extender proves to be better, what about the loss of 1-2 stops of light? I've done my best to keep the exposures consistent on my tests, but there are some differences.

There are six different split-screen tests. Can you tell which extender is which? Yeah, you probably can. But just to make it a little harder, I have randomly placed them on each side of the screen, so "A" on one test is not necessarily the same as "A" on the next test.

In a week or two I will reveal which one is which in each of the tests. Until then, you can guess. Obviously some of the quality is lost when posting online, and slight differences will be harder to detect, but that's just the way it is. If you'd like to visit my offices, I'll show you the raw files. :-)

I hope this is helpful to someone else, because I know it was for me. I now have a better feel of when to which extender.

put up or shut up ;)
 

i'll bite... I think (A) represents the optical extender in all instances.

Does the DE also reduce camera shake? Seems so if B is the DE.

I presume you judge the extender to be effective (or you wouldn't have posted the test!) and on my laptop they look very close. A great deal better than a simple digital magnification of an encoded frame.

well... show the footage on a "normal" fullhd screen and its easy to see.

In all my XDCAM HD422 trainings I held we jumped into "dig extender" and saw the result instantly on a 40" HD Screen - and everybody considered this as a "nice to have" option just in case you HAVE to get closer but cant do it another way.

If played out in SD the results are (of course) better. If you use a bad optical extender (or an out of focus extender), dig.Ext. may be the better option.

ULi

[QUOTE=Doug Jensen;1517780It is rumored this will be added to the PMW-350 and/or PMW-320 later this year via a firmware update.[/QUOTE]

One of the first interesting points I noticed in reading my PMW-350 manual is the viewfinder display option in having the digital x2 extender on status, even though the camera does not have this feature at present. Why have it if it wasn't going to be featured at some point in time. Hopefully the rumour will be truth as I have a ZA17x7.6BRMs58 lens coming from Japan in a few weeks, so I might just be able to get that long shot after all. We shall see.

I've always found that the 2x on the lens has a softer image. I would guess the digital extender is much sharper.

Doug,
Good to see the ice has melted.
Sharpest
1 B
2 A
3 A
4 B
5 A
6 B

I'll guess Optical on all above.

I almost forgot I was supposed to follow up with this thread. For those of you who have been waiting breathlessly in front of your computer for these very important results, I apoligize for keeping you in suspense.

Uli, maybe so, but you didn't go out on a limb and actually post your guesses, did you? :-)

Greg, you're wrong on two.
Dennis, you're wrong on one.
Ivan, you're wrong on the same one as Dennis. (posted on Vimeo).

Nobody who went on record (publicly or privately) got them all right.


Optical:
1B, 2A, 3A, 4B, 5B, 6B

Digital:
1A, 2B, 3B, 4A, 5A, 6A

No. If anything, both extenders will accentuate camera shake.
Whatever shaking you see is due to my own sloppy camera work and/or editing.

Doug,

I wanted to take a moment to thank you for your efforts in putting this demo together! It speaks volumes that you are willing to take time out of your business schedule to create and post such comparisons which allow us to draw our own conclusions. I appreciate you taking the time to go above and beyond your outstanding training DVDs and field guides and continue to add a value presence to these forums. (The Vortex products are a very worthwhile investment, for anyone who's considering them, IMHO) Thanks again. It's sincerely appreciated.

FirstlyI would like to endorse Ed's comments above.

Doug,I would have commented on the differences if I could have reliably picked any. I was under the interesting illusion that the incoming picture was the better.

I have an EX3 which does not have a digital extender. The nearest I can get to a digital extender is cropping during editing and I was wondering whether there was any fundamental difference between digital extension and cropping?

Interesting result. As I indicated at the time, I access the web only via my laptop, so didn't expect my evaluations to be reliable. However, checking back on my notes, I got the optical correctly assigned in all cases except #2 (the buoy); judged by resolution and contrast. But I found it difficult to differentiate between the optical and digital extender.

Ed and Alastair, thank you for the nice comments but I'm not doing anything that other people on the forum aren't also doing. Everyone contributes what they can to help everyone else.

To answer the question about cropping; "zooming" into the footage 50% in post doesn't look anywhere near as good as shooting with the digital or optical extender does. Sony is doing something inside the camea that is more sophisticated than just doubling the size of the pixels. I'll post an example if I can find the time.

Curious... if they can add an electronic digital extender via firmware update to the 350 and 320, why then couldn't they do the same on the EX1/3? So many times I use the expanded focus and think: "Wow, I wish I could record this shot."

Of course if you do the zoom in camera in the DSP you can use the full pre-processing bit depth (I think it's 14 bit on the 350) before any compression artifacts are added and the bit depth reduced to 8 Bit.

Hi Doug,

I reviewd the footage thru vimeo , no-scaling, to do my guesses before I found your published results.

Interestingly, me results are:
You can see higher resolution on the optical ones, but if you didnt do the A/B in one screen it would be VERY hard to judge it.
I found it more easy with texts (boat´s name etc.).

I would love to see something similar in 1920x1080 (vimeo was 1280x720).
From my trainings, optical was a clear winner in FullHD over the digital extender.

But anyway, I am impressed how close both pictures compete to each other, especially if you have no A/B comparison...

ULi