LINEAR ZOOM

[David Porter]

Well it isn’t. Demo – Pick a slide and customise it to say 10 seconds. In Objects and Animations create a keyframe at the 10 sec mark and change the zoom to something huge say 1500 and click play. You will see that you rush very quickly into the image at the start and you get slower and slower towards the end. If you now click on the “accelerate” tab on the zoom section and press play you will get something much closer to what I would call a linear zoom.

Having done some measuring I find the image expands at a linear rate i.e. a 1 cm square increases to 2cms, 3, 4, 5 cms after say 1,2,3,4,5 seconds respectively but this is not the same as the effect of getting closer to the image at a constant rate. I think that it has something to do with the angle of view and it is the change of the angle of view that should be linear with time. Any comments?

[trailertrash]

Always been confused by that Mick. Still dont get it. The sharp start and slow end baffles me.

Andrew

[Lin Evans]

Hi Mick,

A long time ago, there was lots of discussion on this. The "linear" zoom is linear (it's been carefully measured) but if you want it to appear like you expect, click the box next to "perspective correction for zoom" on the "Common" tab. If you do a search, you should find pages of information on this from a couple years ago.

Best regards,

Lin

[David Porter]

Hi Lin,

Thanks for the info on "perspective correction for zoom", another bit of PTE I didn't know about. It does not work exactly on my demo as it now appears to quicken when getting close to max zoom but I can tweek in "settings" to give the required result. So should I ever want to use a massive zoom like that I shall know what to do.