B4 Mount on Epic

[Paul Moss]

I wanted to see if i could get any use out of a set of Canon HD-EC cine zooms that are B4 mount.
Yes i know all the dribble about these lenses and that there designed for 3CCD chips etc.......but stuff all that......! i want to try one of these lenses on my EPIC and see what happens........
So i found a maker of a B4 mount for EPIC and here are the results so far........(i do need to do more testing as the frame grabs below are at 10:1 compression from EPIC, next time id shoot 2KHD in 3:1.........)
I will post some more frames as i test this further.....and hopefully some footage.......
cheers
Paul

[Pete Lutz]

Good work Paul. I'd like to see more images and hear your thoughts on the experiment.

[Michael Brennan]

Any footage yet paul?


Mike Brennan

[Robert Berger]

Any footage yet paul?


Mike Brennan

Like to see some too, i've got a nice B4 Fujinon lens 7,6-135mm

[Michael Lindsay]

Is it a optical mount or just mechanical?

Thanks

M

Ps wide shots with fine detail should show up 'issues'

[Max M.]

looks just mechanical, also want to see some footage!, who is manufacturer?

[Pawel Achtel]

I was very curious too. There is some great 2/3" glass out there, like the stabilised 44x zoom, for example.

Can you shoot a 5-10 degree slanted black rectangle or any other sharp edge in the centre and in the corner of the frame? I can put it through Imatest and spit out MTF charts and see what we've got. I have a proper printed SFR chart too, if you have a chance to borrow it from me some time :)

Here is how an ideal SFR chart looks like.

[Paul Moss]

Well after much fiddling with both the B4 EPIC mount & the B4-PL optical adapter, id have to say that the B4-PL optical adapter is the better choice........
It appears sharper, there is no vingetting, which brings me to the B4 EPIC mount
Im having an issue with vignetting on one side of frame with the B4 EPIC mount, which is wired that only one side vignettes....?
Maybe the mount is not optically centered to the sensor....? who knows......i am sending it back to the manufacturer to be checked.
The B4 mount itself is just mechanical, so no optics inside.

Max i got the mount from http://en.foto-akcesoria.com.pl/

Pawel i may take you up on that test just for a laugh, im not expecting anything amazing from this set up, but i feel its a really good option for doco and long lens work.........and yes a 44X HD zoom would be a great test........
cheers
Paul

[Pawel Achtel]

Paul, I have great 25x and 13x Fujinon ENG lenses we could test too. Maybe we could do a quick test at the next Jim Hare's meeting? I would be very interested in the results.

[Dave Blackham]

Ive tested the Abekas convertor and the IBE HDx2 and HD35 convertors against a Leica 100mm f2.8 lens which is as sharp as we can find. All of the convertors perform differently and we had different results depending on the convertor used on different lenses. Most of our testing was done with Canon HJ18 and HJ40 lenses. The first point Id say is they all performed much better than Id thought they would. Its dependent on the lens of course but given e good example then you can get good results. We thought it only really worth doing to get an extended zoom range at the tight end as theres plenty of wide glass around for Epic sized sensor cameras unless theres a particular need to use 2/3 wide lenses. What we did notice was thought the Abekas is a useful convertor it was a little soft compared to the IBE x2 and 35 convertor. The main thing to consider is if you can use the x2 convertors, then are infect just doubling the image circle so if the image circle was say 13mm then it would become 26mm or if 17mm then would become 34mm and so on. Some lenses did vignet through the zoom range and also were affected by aperture such as the Canon HJ18 it performed as follows with the IBE HJx2.

IBE x2

4kHD

28mm at f2.8 Looks good no vignette
320mm approx no vignet but on the edge f2.8
500mm f2.8 slight darkening in corners probably not a big deal though.
500mm f7 ish no darkening on corners even ilumination.

There is a loss of light through the convertor but easily coped with for our intended purpose. If you used the HD35 convertor then there greater light loss but it does cover the whole Epic sensor. Some lenses will be fine with just the HDx2 but you need to check image circle for the lens your intended using.

I do have some test frame examples Ill try to post here if I can work out how to get them up full res.

We were pleasantly supprised by all of the convertors but you need to be starting with a good lens which is well set up to start with.