580EX beamwidth anomaly - who goes first?

Hi, Dave,

supra_dave said:

I don't have a 20D anymore so I can only check this with my XT at
the moment and my 580EX works as described above. Well, almost...
It follows the lens zoom position so;

lens ~ 580EX
35mm ~ 35mm
28mm ~ 28mm
24mm ~ 24mm
20mm ~ 24mm
17mm ~ 24mm

CnF set to 0 and the LCD panel is showing its sensor crop icon. My
580EX is now exactly a year old.

Click to expand...

I suspect you are reprting the numbers shown on the status panel. They do not tell us the head position. Rather, they indicate the reported lens focal length. However, they are "rounded" to a number from the set of head positions (which makes no sense) and so it is easy to think that they indicate the head position.

To check for Behavior X vs. Behavior Y, set your lens to its lowest focal length. Then slowly increase the focal length. (Keep the shutter release half pressed so the camera will be sure to report the focal length to the flash unit.) Listen for the sound of the head shifting.

If you have Behavior X, the head will shift as the focal length reaches(if within the range of your lens) 35, 50, and 70 mm (only).

If you have Behavior Y, the head will shift as the focal length reaches (if within the range of your lens) 17.5, 22, 31, 44, 50, and 66 mm (only).

Best regards,

Doug

Visit The Pumpkin, a library of my technical articles on photography, optics, and other topics:

http://doug.kerr.home.att.net/pumpkin

'Make everything as simple as possible, but no simpler.'

...you discover that behaviour Y is just the beginning of another problem?

I would be very glad if behavior Y user could report how the 580EX zoom range cover the field when in 1.6x sensor detection mode.

Few months ago I posted some indoor test shots to Doug showing how my behavior X flash works (or do not works...) at short FL with CF-11-0.

It would be nice to see test shots taken with newer units shots to see if it really performs as expected... I know this is in fact another story but we should start to take it into account if some day we'll have the opportunity to pay for an X to Y up-date.
Ciao, Enrico

n/t

Guys,

A bit more on the odd wide-angle focal length setting of Character X (faulty) 580EX units. There's another quirk - see below.

Doug Kerr said:

HoppyUK said:

Hello guys,

Click to expand...

Click to expand...

[I see now that

Doug Kerr said:

your next remark relates to this, as does a discussion later in
this message.]

Doug Kerr said:

(24mm is the focal length on
the flash LCD panel, but it is different to the zoom head position
you get when setting 24mm in manual zoom mode – this requires
further investigation.)

Click to expand...

Click to expand...

Doug Kerr said:

Doug

Click to expand...

We have established that early production samples of the 580EX (tagged Charcter X in this thread) do not set the correct zoom on the flash head to correlate with 1.6x factor cameras like 20D and 350D, as they should when Custom Function 11 is set to 0.

If you fit a wide lens like a 17-85mm, at 17mm the flash head starts at a setting of 24mm, as indicated by the LCD on the rear panel of the flash, and doesn't move until the lens focal length is increaed to 35mm. This is wrong - it should move at around 18mm, 22mm, and 30mm etc. However, I had assumed that when the flash LCD said 24mm, I was at least getting maximum flash coverage the gun could give me, even though it was obviously missing out on some of the finer increments further up the focal length scale.

But that does not seem to be the case. When set as above, when the flash zoom LCD reads 24mm the flash head is actually set at a considerably longer focal length that I would guess at around 35mm. This measure is estimated from careful visual examination of the head as it zooms - not easy to be absolutely accurate. If you want to try this for yourself, be extremely careful not to trip the shutter and fire the flash or you'll be seeing squares for days.

The fact that it is a lot longer than the 24mm reported on the flash LCD is confirmed when manually setting the flash zoom to 24mm, which immediately forces the head into its position of maximum coverage.

Furthermore, test pictures taken with the camera confirm extreme vignetting, as you would expect, that is not there when manual flash zoom is set.

And finally, if you switch the flash #11 Custom Function to 1 (Disabled) the flash will immediately zoom out to the max-wide 24mm position.

In fact, switching this Custom Function to the 1=Disabled setting appears to rid the 580EX of almost all of its problems, as has been mentioned before. You lose out on the optimised flash coverage with 1.6x factor cameras, but the camera and flash will work together reliably, and without vignetting.

Best regards,

Richard.

In my post above, I orginally thought this was confirmation of a fault characteristic only hinted at before.

Having re-read some posts, I think this problem was evident from the start, but I had overlooked it. Maybe some of you other guys also did, in which case this hasn't been a complete waste of time!

Thanks,

Richard.

HoppyUK said:

A bit more on the odd wide-angle focal length setting of Character
X (faulty) 580EX units. There's another quirk - see below.

Doug Kerr said:

HoppyUK said:

Hello guys,

Click to expand...

Click to expand...

[I see now that

HoppyUK said:

your next remark relates to this, as does a discussion later in
this message.]

HoppyUK said:

(24mm is the focal length on
the flash LCD panel, but it is different to the zoom head position
you get when setting 24mm in manual zoom mode – this requires
further investigation.)

Click to expand...

Click to expand...

HoppyUK said:

Doug

Click to expand...

We have established that early production samples of the 580EX
(tagged Charcter X in this thread) do not set the correct zoom on
the flash head to correlate with 1.6x factor cameras like 20D and
350D, as they should when Custom Function 11 is set to 0.

If you fit a wide lens like a 17-85mm, at 17mm the flash head
starts at a setting of 24mm, as indicated by the LCD on the rear
panel of the flash, and doesn't move until the lens focal length is
increaed to 35mm. This is wrong - it should move at around 18mm,
22mm, and 30mm etc. However, I had assumed that when the flash LCD
said 24mm, I was at least getting maximum flash coverage the gun
could give me, even though it was obviously missing out on some of
the finer increments further up the focal length scale.

But that does not seem to be the case. When set as above, when the
flash zoom LCD reads 24mm the flash head is actually set at a
considerably longer focal length that I would guess at around 35mm.
This measure is estimated from careful visual examination of the
head as it zooms - not easy to be absolutely accurate. If you want
to try this for yourself, be extremely careful not to trip the
shutter and fire the flash or you'll be seeing squares for days.

The fact that it is a lot longer than the 24mm reported on the
flash LCD is confirmed when manually setting the flash zoom to
24mm, which immediately forces the head into its position of
maximum coverage.

Furthermore, test pictures taken with the camera confirm extreme
vignetting, as you would expect, that is not there when manual
flash zoom is set.

And finally, if you switch the flash #11 Custom Function to 1
(Disabled) the flash will immediately zoom out to the max-wide 24mm
position.

In fact, switching this Custom Function to the 1=Disabled setting
appears to rid the 580EX of almost all of its problems, as has been
mentioned before. You lose out on the optimised flash coverage with
1.6x factor cameras, but the camera and flash will work together
reliably, and without vignetting.

Best regards,

Richard.

Click to expand...

Hi, Richard,

HoppyUK said:

If you fit a wide lens like a 17-85mm, at 17mm the flash head
starts at a setting of 24mm, as indicated by the LCD on the rear
panel of the flash, and doesn't move until the lens focal length is
increaed to 35mm.

Click to expand...

No (if we are talking about Behavior X) , it doesn't start with the head at 24 mm (as you get to in a monute) - the reported focal length (which is what is displayed on the panel, in a peculiar way) starts at 24 mm.

HoppyUK said:

This is wrong - it should move at around 18mm,
22mm, and 30mm etc. However, I had assumed that when the flash LCD
said 24mm, I was at least getting maximum flash coverage the gun
could give me, even though it was obviously missing out on some of
the finer increments further up the focal length scale.

But that does not seem to be the case. When set as above, when the
flash zoom LCD reads 24mm the flash head is actually set at a
considerably longer focal length that I would guess at around 35mm.

Click to expand...

It is in fact precisely the "35 mm" head setting. The head can only go to seven discrete postions: "24 mm", "28 mm", "35 mm", etc.

I have emphasized this implication of the anomaly in all my characterizations of it.

HoppyUK said:

This measure is estimated from careful visual examination of the
head as it zooms - not easy to be absolutely accurate. If you want
to try this for yourself, be extremely careful not to trip the
shutter and fire the flash or you'll be seeing squares for days.

Click to expand...

Indeed.

HoppyUK said:

Furthermore, test pictures taken with the camera confirm extreme
vignetting, as you would expect, that is not there when manual
flash zoom is set.

Click to expand...

Indeed. This is why the problem is a problem!

HoppyUK said:

And finally, if you switch the flash #11 Custom Function to 1
(Disabled) the flash will immediately zoom out to the max-wide 24mm
position.

Click to expand...

Yes, just like the dumb old 550EX would do, or a 580EX if used on a dumb old 300D!

HoppyUK said:

In fact, switching this Custom Function to the 1=Disabled setting
appears to rid the 580EX of almost all of its problems, as has been
mentioned before. You lose out on the optimised flash coverage with
1.6x factor cameras, but the camera and flash will work together
reliably, and without vignetting.

Click to expand...

Exactly.

Best regards,

Doug

Visit The Pumpkin, a library of my technical articles on photography, optics, and other topics:

http://doug.kerr.home.att.net/pumpkin

'Make everything as simple as possible, but no simpler.'

no text

This might not be as far fetched as one might imagine.

I envsion doing it through the hot-shoe interface.

Many of the microcontrollers I work with these days are set up to allow in-circuit programming of their flash memories. That can be done entirely with serial communications to the units and this allows for easy, fast field upgrades of the firmware of the devices in question.

The idea is that we (or anyone) can design their hardware and be getting the PC boards fabricated and ready to roll while the firmware is still under development. And even after production, or even later in the field, if we want to update the programming, we're covered. (Imagine that, I made an error or came up with a better plan later - that never happens

This also allows us to have multiple uses for a given board. Depending on what it'll be used for, we just load the appropriate firmware. For what I do, that's nice because I can design a general purpose board with a more powerful controller than the job at hand requires, and put extra I/O on the thing and then I can use that board to do the proposed job but also have it available for other similar but different jobs.

I love it Most of the stuff I do is very limited production for lab equipment that is very specialized. My company doesn't mind paying me to design stuff even if we'll only want five of them because the alternative lab equipment is so outrageously priced that even if it takes a lot of my time to design and program, it's still cheaper than buying the stuff from the "normal" suppliers. Or, as is often the case, there simply is nothing else available to do the job at all.

But for Canon, the economics would be different. For them, if it cost an extra buck to have this serial reprogrammability then they may decide against it. For them, having a bunch of masked ROM processors built might save them over what the flash-based controllers would cost.

But assuming they went with a flash-based controller, there are plenty of pins on that flash hot-shoe connector to allow for this sort of thing I can think of a number of ways to implement this. Remember the old EPROMS that had you put a higher than normal voltage on one pin in order to put them in the "programming" mode? You could do the same thing with one of the pins on the hot-shoe.

Or it could be done entirely via the code you sent if things were handled right, I guess.

And the 580 is plenty new enough to have one of these flash based microcontrollers at its heart.

But it still would not surprise me to find that this is not the case and that the flash units would need to be "fixed" in some other way. It's probably wishful thinking to imagine that things would be so easy.

This is, again, pure speculation and wishful thinking run rampant

The price of the flash based controllers has dropped to where simple ones are only a buck a chip or so and fancy ones are only a couple of bucks. But even so, masked-ROM types are probaby cheaper yet for people like Canon who deal in large volumes.

Well, we could only hope, I guess

--
Jim H.

Doug Kerr said:

Hi, Dave,

Click to expand...

Doug Kerr said:

If you have Behavior X, the head will shift as the focal length
reaches(if within the range of your lens) 35, 50, and 70 mm (only).

If you have Behavior Y, the head will shift as the focal length
reaches (if within the range of your lens) 17.5, 22, 31, 44, 50,
and 66 mm (only).

Click to expand...

Okay... I understand it now..

It only shifts when I reach 35mm on my Tamron and it shifts back @

So you are saying this is wrong behaviour and newer 580EX's have a different behaviour? Interesting...

I got annoyed of my poor flash performance, I only bounce now with a Stofen omnibounce which is better.

--
(Click on my forum name for equipment and equipment history)
Personal photo gallery: http://www.defotojournalist.com/gallery

supra_dave said:

So you are saying this is wrong behaviour and newer 580EX's have a
different behaviour? Interesting...

Click to expand...

That's what's being said. What's happening is that all focal lengths are first being rounded down to the closest item in the sequence 24, 28, 35, 50, 70, 80, 105. Anything from 17-23mm becomes 24mm 'cause there's no lower value in the sequence. Anything from 24-27mm also becomes 24mm due to rounding down. The value of 24mm is the value that's then multiplied by 1.6x in cropped-sensor mode, which gives 38.4mm. This is then rounded down according to the same list of numbers (which correspond to head positions), yielding the 35mm head position. Everything from 28-34mm is rounded down to 28mm first and then multiplied by 1.6x to yield 44.8mm, which rounds down to 35mm in the head position list.

End result, everything below 34mm ends up at the 35mm head position and the first two head positions go unused. All because the flash erroneously goes through the step of first snapping (rounding down) the focal length of one of the numbers in the head position list before multiplying by 1.6x.

David

Hi, Dave,

supra_dave said:

It only shifts when I reach 35mm on my Tamron and it shifts back @

17mm there is no additional shifting.

So you are saying this is wrong behaviour and newer 580EX's have a
different behaviour? Interesting...

Click to expand...

Yes. The newer units have what I call "Behavior Y", which I consider appropriate. If you had that, then when your lens was set to the followeing focal lengths, you would get the following results (I don't what lens you have, so I don't know its range of focal length):

Behavior Y:

Focal length....Eff. focal length....Head position....Implication

17....................27.2....................24....................Safe; best available
17.5.................28.0....................28....................Perfect

20....................32.0....................28....................Safe; best available

22....................35.2....................35....................Essentially perfect

30....................48.0....................28....................Safe; best available

32....................51.2....................50....................Essentially perfect

35....................56.0....................50....................Safe; best available

44....................70.4....................70....................Essentially perfect

50....................80.0....................80....................Essentially perfect
etc.

Now, for Behavior X (which your unit evidiently has), for the same focal length settings:

Behavior X:

Focal length....Eff. focal length....Head position....Implication

17....................27.2....................35....................Inadequate beamwidth

17.5.................28.8....................35....................Inadequate beamwidth

20....................32.0....................35....................Inadequate beamwidth

22....................35.2....................35....................Essentially perfect

30....................48.0....................35....................Safe; best available

32....................51.2....................35....................Safe; not best available

35....................56.0....................50....................Safe; best available

44....................70.4....................50....................Safe; not best available

50....................80.0....................80....................Essentially perfect
etc.

Best regards,

Doug

n/t

John Pane said:

• When the SPEEDLITE 580EX receives image size data from a
supported EOS digital camera (20D, 1DMkII, or later models), the
flash head automatically zooms to match the effective angle of view.

Click to expand...

I think this line alone removes any refuge for Canon to hide behind their ambiguously worded "24mm" statement often referred to. From 44-49mm, it fails to zoom to the 70mm head position, remaining fixed at the 50mm position. This is a failure to zoom "to match the effective angle of view," in a range where the zoom is clearly physically capable of doing so.

In my opinion, based on their repairing this behavior in later versions of the unit, Canon considers this a defect and is fully aware of it. Furthermore, the defect inflicts measurable harm on any user of the unit, by leading to corner vignetting for focal lengths between 17 and 22mm. I think only the obscurity of the problem (or of its understanding) prevents a large, annoyed group from forming and filing a class-action law suit.

David

Doug Kerr said:

Behavior Y:

Focal length....Eff. focal length....Head position....Implication

30....................48.0....................28....................Safe; best available

Click to expand...

This line of the table should have 35 in the head position column.

David

HoppyUK said:

Canon knows it has a problem, and their PR
department will be monitoring this thread, assessing the possible
extent of it and discussing the options. It will take several weeks
before we will be in a fair and reasonable position to brand Canon
as either a really good customer-focused brand, or a bunch of guys
in shabby black hats.

Click to expand...

Do you really thing they'll stop by, read this thread and voluntarily come forth with a solution? I hope you're right, but, in all likelihood, someone will have to push them to act.

David

If somebody has a piece of equipment they think is not performing properly, they should contact the manufacturer and request them to correct it.

If somebody will give me an "old" 580EX, I will certainly do that. ("In warranty" would certainly be best.)

Best regards,

Doug

n/t

Doug Kerr said:

If somebody has a piece of equipment they think is not performing
properly, they should contact the manufacturer and request them to
correct it.

Click to expand...

I did. They refused to acknowledge the problem and they refused to fix it. Yet they altered the design (software or hardware, I'm not sure) to fix the problem they refused to acknowledge.

I'm going to ask again and see what they say this time.

--
Lee Jay
(see profile for equipment)

Hi, Lee Jay,

ljfinger said:

Doug Kerr said:

If somebody has a piece of equipment they think is not performing
properly, they should contact the manufacturer and request them to
correct it.

Click to expand...

I did. They refused to acknowledge the problem and they refused to
fix it. Yet they altered the design (software or hardware, I'm not
sure) to fix the problem they refused to acknowledge.

I'm going to ask again and see what they say this time.

Click to expand...

Good idea. Things change.

Best regards,

Doug

Visit The Pumpkin, a library of my technical articles on photography, optics, and other topics:

http://doug.kerr.home.att.net/pumpkin

'Make everything as simple as possible, but no simpler.'

I think the issue is: there has to be a complete path within Canon from people who understand the problem, to people who can make a decision to replace/repair defective units under warranty, to the front-line customer support staff.

From our experience so far it appears that attempting to forge this path bottom-up, via customer support staff, may not be all that effective.

Some of us are apparently hoping that there is another way to make this connection occur within Canon. Thus the attempts to get Chuck Westfall engaged in the process, or the hopes that "somebody" is watching these forum discussions.

John