420 EX Assist Beam with Elan 7e

[ruben leal]

Canon claims their 420 EX's Assist Beam is a cross patern

intersecting at the center focusing point, and extending vertically

and horizontally to all the Elan 7e's focusing points.

 

I just realized my speedlite only emmits the vertical pattern when

used in the manual modes (P, Tv, Av, and M), and the cross patern is

turned on only when in the auto modes (Green, Potrait, Macro and

Night).

 

Is there something wrong with my camera-flash combo? Does anybody

know why this happens? Is there a way to use the cross-pattern in the

manual modes? Is there a Custom Function combination that is turning

off my horizontal assist beam while in the manual modes?

 

I mainly shoot in Tv and Manual, and then I would like to take

advantage of the extra autofocusing capabilities of the central cross

sensor with the aid of the cross shapped assist beam in poor light

conditions while in the manual modes.

 

 

Regards,

Ruben

[sheldonnalos]

Ruben -

 

I just grabbed my Elan 7 and 420EX sitting next to me and I think I have your answer.

 

In the auto modes, the camera takes away focus point selection from the user, so the camera decides which focusing point to activate for a shot and therefore the cross pattern is fired by the 420EX for both vertical and horizontal sensors. (Note that the flash is turned off for the Landscape mode, and that the focus assist light does not fire for the Sports mode, since it uses AI Servo focus).

 

In the manual modes, the focus assist light will fire for only the selected focusing points. For example, if you select the top focusing point it will fire only a vertical pattern, and if you select one of the right or left focusing points, it will fire only a horizontal pattern. If all focusing points are active, it will fire the full cross patter with both vertical and horizontal grids.

 

Basically the flash is only firing the focus assist lights that you need for your selected focusing points.

 

I did note that when only the central focus point is selected, the flash projects just the vertical beam (if you look closely there are some horizontal components to the vertical beam). This did not appear to hinder focus speed for my setup. My Elan 7, 420EX, 50mm f/1.4 combo would focus on a blank white wall in a dark (near pitch black) room at distances of 2 - 20 feet, usually within a second.

 

Hope this helps!

 

Sheldon

[PuppyDigs]

Sheesh Sheldon, that was a good answer! You have keen powers of observation.

[ruben leal]

Thanks for your answer Sheldon, that's exactly what I was looking for. Very clever, by the way.

[jimstrutz]

I don't have an Elan 7 or a 420EX to work with, but I have never seen this mentioned anywhere before. Interesting observation. I wonder if this is related to the reason that the 550EX only lights up the five horizontal sensors?