Many other have already given good advice, but i would suggest an middle/light grey on the screen to give the fingers around the phone a natural lighting from the screen, that helps sell the shot much better than just a black screen and the too dark contact of finger on the screen in the recording. This is more important in a dark setting, maybe not so much in a brightly sun lit situation like you show here, then the relative small amount of light the screen gives wouldn't be so noticeable.

Avoid tracking markers on screens, with Mocha they usually is not needed, and you have to spend time removing them. :-)

In the case you show with the sun backlight i would have tried to put a white screen on the phone to see if it would show at all in that lighting, and if not, i would put on markers in this one case to just get an easier track and just fake the reflection

...and i would again probably use Mocha to track a mask for the finger... Mocha is really a nice tool

btw. i love this list when so many contribute with good answers to questions. :-)

- Robert 

2014-06-02 18:18 GMT+02:00 Mr. Eric D. Kirk <AE-List@media-motion.tv>:

Well, all said and done, I guess I need to rethink the use of track dots for my next screen replacement.

 

Just for clarification though for those Mocha experts, if the dots are ripped pieces of tape (essentially making them square), with more distinct corners, does Mocha treat it any differently?

 

I was always of the thought that something distinct is better than nothing.

 

Thanks,
Eric

On Mon, Jun 2, 2014 at 11:55 AM, Ross Shain <AE-List@media-motion.tv> wrote:

On that note, a cool trick is to go into the clip tab in mocha and adjust the color space, gamma, etc. The clip tab color settings occur first in the stream, so it will influence the tracker, no need to render.

That said, it is extremely rare that I use this technique. 

Sent from my iPhone

On Jun 2, 2014, at 11:35 AM, "Teddy Gage" <AE-List@media-motion.tv> wrote:

Hey if the shot is over or under exposed there is a trick I use to give mocha more tracking info - We were shooting very flat ARRIRAW 4444 for a project and I was having a really hard time tracking a few shots, so I re-rendered the footage with the LUT baked in and majorly boosted the levels contrast. When I ran the footage back through Mocha it had a much easier time locking on to the plane edges. Then I just applied the track to the original footage and it worked great. So try adding sharpening and balancing the  histogram, and re-rendering just for the tracking bits, it could help. Unfortunately you do have to render it first, as mocha will not pick up any AE filters just applied on the timeline

On Mon, Jun 2, 2014 at 11:27 AM, Roei Tzoref <AE-List@media-motion.tv> wrote:

thanks Ross, that sounds like a good compromise.

I will look in the tutorial as well.  from scrubbing through I see it has an ipad screen replacement with real reflections

it looks proper lit (not like mine which is very dark and creates more problems).

about the shot to give I will contact you directly in a moment.

On Mon, Jun 2, 2014 at 6:12 PM, Ross Shain <AE-List@media-motion.tv> wrote:

I would personally recommend avoiding green and simply have the device set to display a medium/dark grey screen that will show "some" reflection but also give you visual reference of the screen edges against the black border. In general, if you track the edges and avoid the actual screen, mocha should be fine. Also note, placing small white dots on a black screen is not necessarily going to "help" mocha. mocha's planar tracker is looking for texture. So if possible, use a pattern and not a "round, white dot". 

Here is a link to a free 1.5 hr training webinar that specifically covers using mocha for difficult screen inserts. I would highly recommend this to any AE artist that has used mocha for the basics, but does not fully grasp some of the more advanced techniques for avoiding reflections, handling the really difficult tracks or the AdjustTrack module. 

http://www.imagineersystems.com/videos/webinar-replay-tracking-dificult-screens-with-mocha/

Imagineer is always looking for difficult tracking shots to use for tutorials and testing, so if you have any - please let me know. 

Cheers,

Ross

-- 

Ross Shain
Chief Marketing Officer
Imagineer Systems - developers of mocha planar tracking and visual effects tools.

www.imagineersystems.com 

On 2 June 2014 10:40, Teddy Gage <AE-List@media-motion.tv> wrote:

We use small tracking target stickers at each corner of the screen and mocha takes care of the rest. How experienced are you with mocha? Even the most difficult tracks can be accomplished manually but there are a lot of ways to do it you may not know about. There are some great advanced tuts online even pros could learn from.

We never use green because as you said it blocks reflections, but more importantly you can get green spill on the actors that is harder to manage.

On Jun 2, 2014 10:28 AM, "Roei Tzoref" <AE-List@media-motion.tv> wrote:

Hey y'all

I recently tracked different kind of Iphone and Ipads screen replacements

with different methods, and cant be sure whats the optimal way of preparing the shoot.

my question is:

do you use green on iphone and ipads where good reflections are needed to sell the shot?

my considerations are:

on one hand:

with green sticker -> better track and maybe easier roto, but you do have to remove it

and no reflections.

on the other hand:

without green sticker -> more rotoscoping, sometimes difficult track, but good reflections.

the way I decided doing it was with no green because mocha can track just with

the shapes and proportions and the green I get usually its just a pain to remove

and although helps me with the track, I do have to remove it and replace it. and

usually it doesn't help me with keying it because the shot is lit for the main action

and not the green inside. the problem is I got a shot with bright sun behind

and the track was very hard. a green would have at least help with the shear shift.

what do you recommend as the best course of action for iphones and ipads

and GUI screens in general (where you need the reflections)?

thanks

--

Ross Shain
Chief Marketing Officer
Imagineer Systems - developers of mocha planar tracking and visual effects tools.

www.imagineersystems.com
Phone: +1.646.298.6458 | Fax: 646.808.0831 | Email: rosss@imagineersystems.com

Find us online:
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_____________________________

VFX & Motion Graphic Artist
teddygage dot com

--

Eric D. Kirk | Kirk Productions

Hidden in the Woods | VFX

The Night Visitor | VFX

443.206.1347

www.kirkproductions.com
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