FS700 With Macro Lens Issue

[Chris Slade]

Hey guys

First time poster here and hope you can help.

I recently upgraded from a Panasonic AC-160 to a Sony FS700 with a couple of Canon lenses and so far everything has been fantastic. Obviously with such a change in camera my footage looks leaps and bounds forward on what I was providing in the past.

Although last week I hit my first problem..... I film a lot of mobile phones for one particular client and when I was using my new Macro lens I was getting a strange line across the screen.

Now I have been filming phones for a few years now and obviously have had to change my shutter speed to adapt to the the refresh rate and stop strobing but no matter what I do this problem doesnt seem to go away.

I am shooting with a FS700, EF-E Mount Speedbooster with a Canon EF 100mm f2.8L Macro lens.

Whenever I get below a focus of 2 feet the line appears: imgur: the simple image sharer

I have tried lots of different settings and as I said above 2 feet its fine and with my other lens (24-70mm) I dont see the line. Am I being really stupid and it is a refresh issue or is there something that can be done?

Any help/suggestions appreciated

Cheers

[Chris Hurd]

Hmm... looks like a refresh issue to my uneducated eye. How much trouble would it be to shoot beyond two feet and crop in post? Welcome to DVi by the way.

[Chris Slade]

Sorry I thought I should add what the exact settings where

1080P, 25 FPS, 1/60th shutter speed.

These are the same settings I used on the Panasonic and obviously I know its a completely different camera/lens I had no issues like this so there must be something I am not understanding here.

Yeah, I could do that Chris as it certainly is an option but I bought the macro to give me the ability to get incredibly close to the phone to really show off the detail. Seems I was wrong, oops!

[Chris Medico]

Do the lines move or are they stationary?

Can you post a short video clip in addition to the still image?

[Chris Slade]

Yep, give me a n hour or so and I'll upload a short video

Cheers guys

[Chris Slade]

Lines! - YouTube

Link attached. Any other info, questions, suggestions please go ahead :)

[John Mastrogiacomo]

Originally Posted by Chris Slade

Yep, give me a n hour or so and I'll upload a short video

Cheers guys

Try it out in sun with something that isn't electronic. You need to start eliminating things. It could be something weird with the LCD display on the phone at that magnification.

[Colin Elves]

It doesn't look like a screen refresh issue to me, it looks more like a polarisation thing - it may be related to the OLFP in the camera, I dunno. You could try shooting through a polariser, see if that makes a difference.

[Chris Medico]

That is coming from the polarizing screen on the LCD.

[Chris Slade]

Hey guys

Thats a good shout. I never thought of that.

Are there any particular things I should look at for a polariser or should I just buy a multi pack of different strengths and see which one works best?

[Colin Elves]

Polarisers don't really come in different strengths (well, they do, but it generally reflects brand quality more than anything) but if you have a pair of polarising sunglasses you could try shooting through them. But, if I'm honest, I suspect it will make it worse rather than help.

Just out if interest - that's not some sort of glasses free 3D screen on that phone is it? I'm just wondering why it might do that. I shot a macro shot of a mobile (iPhone) for a viral end of last year and had no problems with the screen.

Also, have you tied varying the angle you shoot it at? Eg straight down, more acute etc

[Chris Slade]

Nope just a regular Sony Xperia Z2.

I'll do some more tests on this weekend and get back to you. In the process of picking up a polariser to see what effect it has

[Colin Elves]

Anything to report? It's be interesting to know if you found a solution in case I encounter it myself at some point.

[Alister Chapman]

Looks like aliasing and moiré to me. As you get closer to the screen the camera is able to resolve the individual pixels and this can lead to aliasing and moiré. The phones in the images are not perfectly parallel with the camera so the actual point of sharp focus will be a narrow band across the phone's display. If you fractionally de-focus the picture does it go away or move forwards/backwards along with the focus point? A touch of diffusion with a soft focus filter would fix it. I guess you previous camera wasn't sharp enough to show this effect up ;-)

[Colin Elves]

good call Alister! Looking at it again, I think you're right.