Canon 550EX Speedlite

[robertwgross]

In the hour before a wedding, I was getting my rig adjusted. I had my 550EX Speedlite on a flash bracket with my D60. I got the cable ends all screwed on tight, and then I wanted to fire a test shot just to make sure that everything was normal.

I moved the zoom lens in and out a bit, then half-pushed the shutter button, and I expected to hear the buzz of the 550EX's zoom feature. But it did not buzz. I looked at the 550EX's display, and it said Manual Zoom was in effect. Hmmm.

I fooled with it and tried everything, and I could not get it into full auto-zoom function. Well, that is not a show-stopper, so I started to shoot the first poses outside and used the 550EX for fill.

I kept fooling with it, and FINALLY I looked at the front of the 550EX. I had the wide diffusion filter pulled down, which is used only with very wide lenses. As soon as I pushed the little plastic thing up and away, the flash kicked into full auto-zoom function.

Live and learn. I bet I don't make that mistake again. However, it is good that it does not prevent the flash from firing. It just spreads it wider.

---Bob Gross---

[kn_guy87]

Thanks for the tip, Bob. I''ll keep it in mind.
Ken

[Belmondo]

I hate flash attachments that are smarter than I am.

[DaveG]

A number of times I've found that the 550EX flash doesn't seat properly in the top of the remote cord.

It look like it does but there's a little too much of the pins showing. If I have a zoom lens on the camera I like to zoom it a bit while I'm waiting to do a shot. If everything is hooked up then the flash read out should react to the change in focal length. When the flash isn't hooked up right then there is no change in the read out and this should tell you something right away.

However if you are using the 550 flash on MASTER in order to control another flash, then the 550 will default to 24mm, which is the widest setting. This gives the widest flash output which hopefully insures that the slaved flash "sees" it and gets the information it needs from the first flash pulse. But it can be very frustrating when the perfectly happy flash is not reacting to the change in focal length and you can't figure out why!

One thing about Canon that I don't understand. The zooming of the lens on the camera tells the flash to zoom in or out. So it's the lens/camera that's controlling this. So why does it follow the full frame 24x36 "focal length". I mean if I have a 50 mm lens on the camera it'll zoom out to 50 mm. But I'd like the flash head to zoom out to 80. It seems that a hard wired internal command inside of each camera model wouldn't be rocket science.

[wolverine]

Hi Guys:

I have a similar experience. I mounted my flash on my D60 and found that it wouldn't fire. I hit the pilot button and it fired with no problem. Well now the panic set in! Then I discovered that the flash wasn't pushed fully onto the hotshoe of the camera. This is what you were talking about DaveG. Also, Dave, I asked that same question about the flash zoom quite a while back. If I am concerned about power, than I will zoom the flash manually. Thanks guys for letting me know that there are other guys out there thinking the same way that I do.

John

[robertwgross]

DaveG wrote:
One thing about Canon that I don't understand. The zooming of the lens on the camera tells the flash to zoom in or out. So it's the lens/camera that's controlling this. So why does it follow the full frame 24x36 "focal length". I mean if I have a 50 mm lens on the camera it'll zoom out to 50 mm. But I'd like the flash head to zoom out to 80. It seems that a hard wired internal command inside of each camera model wouldn't be rocket science.

I think you are saying that it would seem that the camera body would translate the 50mm lens information into 80mm and send that to the flash. Maybe it isn't that smart. Maybe there is a real reason. On the other hand, if it made an error the other way, sending 50mm information as 30mm, then that would create a problem of flash light falloff on the sides of the image. So, if they have to get it wrong, at least they get it wrong on the safe side.

---Bob Gross---

[DaveG]

robertwgross wrote:
DaveG wrote:
One thing about Canon that I don't understand. The zooming of the lens on the camera tells the flash to zoom in or out. So it's the lens/camera that's controlling this. So why does it follow the full frame 24x36 "focal length". I mean if I have a 50 mm lens on the camera it'll zoom out to 50 mm. But I'd like the flash head to zoom out to 80. It seems that a hard wired internal command inside of each camera model wouldn't be rocket science.

I think you are saying that it would seem that the camera body would translate the 50mm lens information into 80mm and send that to the flash. Maybe it isn't that smart. Maybe there is a real reason. On the other hand, if it made an error the other way, sending 50mm information as 30mm, then that would create a problem of flash light falloff on the sides of the image. So, if they have to get it wrong, at least they get it wrong on the safe side.

---Bob Gross---

One presumes that they wouldn't get it wrong.

[Bloop]

DavidG

But the 1.6 mulitplier is a fov crop and not an increase in focal length. Thus the camera for exposure's sake is behaving correctly in sticking to the 35mm focal length.

[DaveG]

Bloop wrote:
DavidG

But the 1.6 mulitplier is a fov crop and not an increase in focal length. Thus the camera
for exposure's sake is behaving correctly in sticking to the 35mm focal length.

It IS an increase in effective focal length. It's like changing camera formats.

An 80 mm lens is a wide angle on 4x5, a normal on 6x6 and a short telephoto on 35 mm.
The focal length has not changed but the area of coverage has. The CMOS in my 10D
can't see all of the image circle that these lenses throw so why would I care if the flash
doesn't cover this unseen area?

The flash throws a cone of light, small near the flash and then widening. On most flashes
this cone is fixed except for the use of an add on wide angle diffuser. The 550's head is
designed to move internally to choose the optimum cone shape depending on the focal
length selected. For wide angles you want a cone that gets wide very quickly, and for
telephotos you’d want a cone that's narrower. This way you wouldn't have fall off with
wide angles and yet would concentrate the light on subjects that are farther away.

So if I used a 50 mm lens on 35 mm I'd want the flash to zoom to 50 mm so there'd be no
fall off. On the smaller 10D CMOS, while still using the 50 mm lens, I'd want the flash it
to zoom out to (indicated) 80 mm.

[Webster]

Thus the camera for exposure's sake is behaving correctly in sticking to the 35mm focal length.

The flash unit's focal length adjustment has no bearing whatsoever on the exposure. It only affects the maximum distance the flash can be used for.

I'm not sure I'd go so far as to call Canon's choice here wrong. But if I had my druthers, I'd sure rather have the extra distance that would be gained by the camera reporting the effective focal length rather than the real focal length.

[Bloop]

webster wrote:
Thus the camera for exposure's sake is behaving correctly in sticking to the 35mm focal length.

The flash unit's focal length adjustment has no bearing whatsoever on the exposure. It only affects the maximum distance the flash can be used for.

I think so too. It was late. I was tired... I meant to say that the evenness of the light would be affected. This link (sorry so long) is what I was referring to - Chuck Westfall of Canon.

http://65.110.81.28/ubbthreads/showflat.php?Cat=&Board=UBB8&Number=173790&Forum=,,,f8,,,&Words=550EX%20zoom&Searchpage=3&Limit=25&Main=172460&Search=true&where=bodysub&Name=&daterange=0&newerval=&newertype=&olderval=&oldertype=&bodyprev=#Post173790



I'm not sure I'd go so far as to call Canon's choice here wrong. But if I had my druthers, I'd sure rather have the extra distance that would be gained by the camera reporting the effective focal length rather than the real focal length.

[robertwgross]

I keep looking in the B&H catalog, but I can't find any druthers. Everybody else seems to look for them also.

---Bob Gross---