EX3 with Canon KH20 and SD lens test results

[Alister Chapman]

Just been playing with an EX3 and I wanted to see how it performed with different lenses. I used 3 lenses, the stock EX3 lens, A Canon KH20x6.4 1/2 inch HD lens and a doggy old 2/3 inch SD lens. The camer was setup using the stock factory picture profile.
The stock EX lens does a very good job, I have always considered it to be a reasonable lens even though it does suffer from a little barrel distortion and when I looked at the video the pictures looked good and sharp with the camera's CA correction doing a good job. Next I looked at the Canon KH20. At first it was at F11 and I it looked a little soft, when I stopped down to F4 however the sweet spot for this lens the pictures sprang to life. The image was clearly sharper than the stock lens and looked to have richer dark areas, although this could be down to the changing light. Looking at bright high contrast areas I can see some CA, but overall I think the EX3 looks quite a bit better with the KH20.
As for the old SD lens. Well to be honest it performed better than I expected. But any wider than F8 and it really started to look very soft and beyond F5.6 it looked pretty grim. Not much more CA than the KH20.
You can download frame grabs from the lenses here http://www.xdcam-user.com/forum3/download/file.php?id=1

[Ned Soltz]

Thanks for posting the images and it is definitely reassuring that the stock lens held up so well. I would have expected the results with the old 2/3" lens but I suspect that some folks will find applications where they can get away with it.

While I await my EX-3, then, a lens question for you.

The manual has a procedure for adjusting backfocus and storing profiles.

Did you need to adjust the backfocus on the stock lens? Did you perform the backfocus adjustments on the two lenses you tested?

Appreciate your images...

Ned Soltz

[Tom Hardwick]

Originally Posted by Alister Chapman

But any wider than F8 and it really started to look very soft and beyond F5.6 it looked pretty grim.

I'm sure you meant to say 'any smaller than f/8' rather than any wider, as diffraction losses will start to become apparent with ½" chips when a lens is stopped down past f/5.6. Maybe that's what you meant by saying 'beyond f/5.6'?

tom.

[Tom Roper]

Originally Posted by Alister Chapman

The image was clearly sharper than the stock lens and looked to have richer dark areas, although this could be down to the changing light.[/url]

Between the shots at f4, I don't see a sharpness difference as much as a lot more contrast that appears to owe more to a pronounced difference in the lighting, one casting well defined shadows, the other flat and diffuse.

[Alister Chapman]

Certainly the lighting is making the KH20 look better, damn clouds acting as diffusers, but I am sure the KH20 is still a touch sharper. Watching the clips the KH20 certainly appears to be a little sharper. To be honest this surprised me as I have never considered the KH20 to be particularly sharp, what I was actually expecting to see was the KH20 being softer than the stock lens so I was pleasantly surprised. I also thing I'm seeing less CA with the KH20 on the EX3 than with the KH20 on my F350, this needs further testing to confirm.

Yes I did mean smaller or more stopped down. It's surprising how early the diffraction starts to take effect, I'm not convinced that the softening at F5.6 on the KH20 is all down to diffraction.

When you use a non-standard lens you don't get the back focus setting in the menu any more. Back focus is adjusted in the traditional manner by adjusting the rear element of the lens. I didn't need to re do the back focus on the stock lens when I put it back on and it appears to track accurately with and without ND's. There are adjustments for flare and shading with memories to save those settings for different lenses but I didn't perform these adjustments.

I was surprised by the thick piece of glass in the lens adapter, but guess it must be there for a reason.

[Tom Roper]

The CA may have been falsely attributed to the KH-20. It can originate in other places, like the prism. The EX should be correcting for CA with some processing as well. Anyway, it looks great.

[Zsolt Gordos]

Alister,

While I don't intend to hijack this thread, I think my question is appropriate to ask here.

In the XDCAM-user forum - which you have referred to above - I have read about the short back focus distance which serves the purpose of using wide range of lenses, such as SLR glasses.
I am very interested in this matter, having a number of Canon still lenses and kind of dislike the hassle and bulk coming with the available "adapters" (M2, Letus, etc.)

My understanding is that with EX3 it will be possible to use the SLR lenses with a much smaller "connecting unit" straight in front of the sensor. This unit is called relay lens if I am not mistaken.
Without entering much into the physics of this method, could you please explain how would that work and what to expect in terms of size, picture quality, moving parts inside (if any) and hassle when using it compared to the units mounted in front of the camera lens.
I understand that some big lenses would require rails for support (like an 800mm) but in the same time I hope this wont be necessary with an average size lens.
Appreciate to hear your opinion on this. I am in the process of deciding between EX1 and EX3 and this would be one major factor in the decision. I have no chance for the time being of thinking about a KH20 :)

[Steve Shovlar]

Alister, looking at those images, all show CA except the stock EX3 lens. IMO the stock lens looks the best of the three.

[Phil Bloom]

I shot this EX3 test short: Windsor Waltz HD on Vimeo using that same 1/2" Canon lens on the EX3. Very happy with the results.

[Zsolt Gordos]

Thats a great film, Phil! It would be great to see some shots from the same location with the EX3 lens to compare.