Anyone else have this issue on 1/2" lenses?

[Paul Anderegg]

Brand new $17,000 Fujinon HS18x5.5BERM lens on brand new PXW-X320...at wide open f1.4, there is severe blooming and softness...looks similar to when I attach my 1980's vintage Nikkor 50mm f1.4 to my Sony A7sII! Closing down to f1.9 eliminates the issue, but this doesn't seem right. I have never seen this happen with a 2/3" B$ lens, and I don't recall ever seeing this back in the 90's with my Sony 1/2" DVCAMs.

The clip below was shot with the 2x digital extender, just for the purpose of expanding the issue visually. It is very noticeable normally, a wide shot of a street scene has car headlights turning into glowing orbs.

Paul

YouTube (Short URL)

[Christopher Young]

Paul ~

Some years back I bought one of f these exact lenses for a PDW-350. I struggled with it for a couple of months then sold it. It had the same issues you are describing. In fact Fujinon's 17x5.5 HD version produced far less image issues.

I then tried and ended up using a 2/3" SD Fujinon, an A18x7.6BDERM-48 with a Canon LO-32BMT 2/3" to 1/2" B4 adapter. The results were amazingly different. Almost nil CA issues and absolutely minimal blooming. That camera doesn't get used much these days but every time it comes out I am pleasantly surprised at the images from that lens. Bear in mind that a 2/3" lens on a half 1/2" chip introduces a crop factor of 1.375. In this example the 7.6 wide end becomes in effect a 10.45mm wide end. Not so good but bare with me.

The other side benefit with the A18x7.6BDERM-48 is that it has a 16:9 / 4:3 cross-over element. This is incorporated into the 2 x housing. The cross-over reduction element was introduced so that if you had to shoot 4:3 on a 16:9 chip you could recover some of the width you lost because shooting in 4:3 mode cropped the edges of the 16:9 sensor which essentially narrowed the lens field of view.

Why is this useful to know? A 2/3" sensor has an 11mm image circle in 16:9. A 2/3" sensor has an image circle of 9mm in 4:3. Now a 1/2" 16:9 sensor has an image circle of 8mm. So what do we have? If the 2/3" cross-over is used on a 1/2" camera the 2/3" 9mm 4:3 image circle covers the 1/2" 16:9 sensor image of 8mm.

Remember in the case of our 7.6mm wide end it became a 10.45mm wide end with the crop 1.375 factor. Now with the 4:3 cross-over engaged it becomes 20% wider. In effect it now comes back to 8.36mm. A much more usable width overall. PLUS there is another benefit. This 20% reduction works much like a Metabones Speed Booster, it recovers lens width AND gains around about .7 of a stop in sensitivity.

This added .7 of a stop sensitivity puts the 1/2" camera virtually back on the same footing as a 2/3" camera in sensitivity. Not often you get something for nothing.

To be honest I was amazed at how much better this top end 2/3" SD lens was than the 1/2" HD glass. This was $26,000 piece of glass when it came out, the very best they made. One of the Fujinon techs also mentioned that if using the lens in its native 16:9 mode which is designed to cover a 2/3" image circle and you then use it to cover an 8mm image circle you are only using the optimal best center part of the optics and less of the edges of the glass which generally makes for better images.

Sometimes the unexpected works. Go figure?

Chris Young
CYV Productions
Sydney

[Paul Anderegg]

Chris, I actually used to run a pair of J22/J11 lenses on my Panasonic SPX800, and would use the 4:3 switch when I wanted a little bit more wide angle. In night ENG, there are many many times where your corners will be in darkness, so it became an actual usable "wide angle converter" for many scenes. :-)

I put my Canon KH21ex5.7IRSE on the X320, and it exhibits the same anomaly...it is quite irritating, as f1.4 was always a big feature for me in regards to looking at these 1/2" cameras. My work JVC HM890 has an HAs18x4.2BERM 1/3" lens, and it is prettiest at f1.4, and if you stop it down to even f2.0 or f2.8, the colors just go away and it looks "dirty" for some reason. Of course with a JVC, you need to stop down to f2.0+ just to eliminate the vertical smear, so ack...wish my station would get real 2/3" gear.

I think I will get an old SD ratio converter lens just to play with, maybe an old J9/J11 just for fun...you got me curious about the SpeedBooster feature :-D

Paul

[Paul Anderegg]

Chris, does the LO-32BMT have an optical element in it, and if so, do you know if it just a corrective element, not a focal converter of any kind?

Paul

[Christopher Young]

Paul ~

Yes it does have a glass element in it and no it has no magnification influence at all. Canon told me that the glass was a correction element to help converge the rays correctly from the 2/3" rear element to the 1/2" chip. Whether that is correct I don't know but I have no reason to doubt my source at Canon.

Whatever it is it works very well. The 22x becomes a 30.25 lens in 16:9 mode. Great for sports. I prefer the 18 x as it becomes a 24.75 x in 16:9 mode which I find is plenty long enough for most things. Plus its smaller and its weight is considerably less. With the 4:3 cross-over it becomes a .7 stop faster 19.8, a very useful length.

Chris Young
CYV Productions
Sydney

[Paul Anderegg]

I got a reply back from an engineer at Fujinon...apparently the image blooming issue is across the 1/2" platform, and is unavoidable. :(

[Christopher Young]

I'll stick with my first response Paul as having owned one Fujinon's HSs 18 x 5.5 lenses I know what a shocker it was. The 17 x 5.5 was considerably better by quite a long shot.

Don't totally agree with your Fujinon man. Even the old 14 x on the EX3's delivered quite remarkable bloom free images. Being an ex network TD I've seen quite large variances in the same make and exact same model of lenses so nothing is set in stone. If you get a good lens you you've got a good one. If you got a poor performer not much can fix it. We used to send lenses back that did meet the standards we felt they should.

Chris Young

[Paul Anderegg]

Remember Chris, we are talking about f1.4...the issue "resolves" itself at f1.9, which the stock lens and the EX lens start at. The issue is the same on the HS18 as well as my KH21...need to test my stations XS17 and XS20 to see how much better newer glass designs might be. Strangely enough, the HTs18x4.2BERM lenses on our JVC cameras are sharp as fruck at f1.4 wide open, no blooming whatsoever...unfortunately, the JVC's, and even the Panasonic 1/3" cameras all exhibit vertical smear when wide open.

BTW, Fujinon has discontinued the HS18x5.5 as well as the HS16x4.6.

Paul

[Christopher Young]

Understood. F/1.4 is overly optimistic in my opinion for a 1/2" lens. Most of the best 1/3" glass can handle F/1.4 but 1.4 is pushing it for 1/2". Look at the top end $30K 2/3" lenses and they are pushing the envelope at F/1.8 - 1.9 and they are the very top end glass with Fluorite elements etc that you don't tend to see in the cheaper glass. As we all know most lenses don't perform at their best wide open. Some fast F/1.2 prime lenses need to stop down to about F/2.0 to minimize flare and increase sharpness to match a good f/1.4 wide open.

Lens speed is a killer under certain circumstances and the circumstances you are shooting under at night with hot light sources of varying colors coming straight into and across the lens is amongst the most demanding of all. Hell it is amazing the pictures we can capture these days and we still complain. But then the saying is that all development is down to the unreasonable man :)

Chris Young