Old flash, lots of power.

[PhotographersWorldWide]

Originally Posted by Wilt

They did NOT call it their '35mm head'...you did.

I think you did.. (at least it is when the 28mm adapter isn't on it)

I would be happy to measure the 45CT at its standard lens coverage (35mm)

Not sure what point you are making with these illustrations of Nkon flashes. The thread and OP comments were about power of the 60CT. I added commentary in post 14 about the relative power of both the 45CT and the 60CT, compared to the so-called GN58 flash units from Canon. I have proven, in successive messages, the power advantage of the 45CT over the 580EX. I made no comments about Nikon flash.

You've proven nothing.

I have yet to see any 580EX comparison or any real world GN for one. You state GN36 for a Canon 58 unit (or 117ft) - thats greater output than the 45CT (@90/95) and more than either of the SB800 or SB900.

If a 580EX is anything similar to an SB800 or SB900, then your extrapolative calculations are simply wrong.

Your latest deduction was "so it (45CT) is more powerful than a 580EX by about 0.8EV". This based on what? - part heresay, part testing a 54EZ, part comparing Manufacturers GN's and then cross referencing them !?

At least our 45CT figures match at around 90/95 GN not 148 - so what is the GN of a 580EX at 35mm Full Frame setting? So far you've just guessed, and nobody has leapt to your defense, apart from comments by the usual ignorant antagonists wanting to take snipes.

Why the apparent hostility ?! Most folks on POTN engage in discussions and debates without antagonism.

Perhaps you should quit while you're ahead, before I discover another test flaw and even higher output?!

Why should I quit when what I've said is correct?

I'm happy to discuss - and I see nothing which I said to be wrong based on the output figures I quoted, but you wanted to throw Manufacturers GN statements at me - which when challenged you explained were wrong !! Not only that - you then go on to use those same (wrong) GN figures as evidence of comparative output differences between your 54EZ and a 580EX.

There is between 0.1 and 0.3 of a stop more output from a 45CT which I already pointed out.. "There is little discernible output difference between a top range speedlight and a 45CT"

Where is the 'putting to shame' you mentioned?

The 45CT is a great flash unit, but its no speedlight killer.

For simplicity of comparison I compared the manufacturer claimed numbers, but if someone else with a flash meter and the 580EX wants to measure the 580EX at 35mm lens coverage (FF), I would be happy to measure the 45CT at its standard lens coverage (35mm) as well as my Metz 54MZ also zoomed to 35mm.

Still waiting on a real 580EX GN.

[flowrider]

/ignored.

It's a wonderful thing.

[PhotographersWorldWide]

Originally Posted by PhotographersWorldWide

nobody has leapt to your defense, apart from comments by the usual ignorant antagonists wanting to take snipes.

One down, two more to go.

[Wilt]

Originally Posted by PhotographersWorldWide

You've proven nothing.

...If a 580EX is anything similar to an SB800 or SB900, then your extrapolative calculations are simply wrong....Still waiting on a real 580EX GN.

Well, to your point, your Nikon tests don't do any better to prove anything about the Canon 580EX power vs. the Metz 45CT either, as a point of fact.

This article lists the 'real guide number' at 35mm coverage angle

• Nikon SB800 = 41,
• Canon 580EX = 39
• Nikon SB900 = 36

http://speedlights.net/speedlights-power-index/


...but they lack any data on a comparable Metz.

One of our moderators did this testing, but the 580EX charts only have 24mm and 105mm measurements, so we have no directly comparable information because angles of coverage do not match. 24mm on FF = 74degree horizontal x 53 degrees vertical. At 24mm, the Canon GN seems optimistic by about 0.4 EV, while at 105mm the Canon GN is optimistic by about 1 EV.
http://photography-on-the.net/forum/...93&postcount=6

[PhotographersWorldWide]

Originally Posted by Wilt

Well, to your point, your Nikon tests don't do any better to prove anything about the Canon 580EX power vs. the Metz 45CT either, as a point of fact.

No they don't - but I didn't grab whatever GN values the manufacturers provided, and the values illustrate what I stated. It has always been my expectation that the best Nikon equipment is matched by the best Canon equipment, so maybe thats where the problem lies?

This article lists the 'real guide number' at 35mm coverage angle

• Nikon SB800 = 41,
• Canon 580EX = 39
• Nikon SB900 = 36

http://speedlights.net/speedlights-power-index/

I'll look there - but I'd dispute those findings based on they are not what I found, and particularly with the SB800 and SB900 values transposed and I only have 0.2 difference at the most.

The Canon 580EX is GN39? That puts it at GN127 ft. In my comparison, and your comparison, that would make it more powerful than a Metz 45.

Do you believe that article?? I don't.

One of our moderators did this testing, but the 580EX charts only have 24mm and 105mm measurements, so we have no directly comparable information because angles of coverage do not match. 24mm on FF = 74degree horizontal x 53 degrees vertical. At 24mm, the Canon GN seems optimistic by about 0.4 EV, while at 105mm the Canon GN is optimistic by about 1 EV.
http://photography-on-the.net/forum/...93&postcount=6

Pointless if they didn't test 35mm.

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[PhotographersWorldWide]

Originally Posted by Wilt

This article lists the 'real guide number' at 35mm coverage angle

• Nikon SB800 = 41,
• Canon 580EX = 39
• Nikon SB900 = 36

http://speedlights.net/speedlights-power-index/


...but they lack any data on a comparable Metz.

They list a 45CT-4 with a GN 47.

You and I have 90/95 for a CT45 - they have 153.. f9 vs almost f16, well thats just wrong.

What were you saying about manufacturers over indulging GN's?? That site goes even further with the top 6-11 flash units all exceeding manufacturers claims.

LOL.. I just read this: "Adding exactly 1 f-stop to the flash meter result in the speedlights.net tests leads to the calculated guide number, so the f16 of an SB-400 becomes f22 = GN22"

[Wilt]

Originally Posted by PhotographersWorldWide

I'll look there - but I'd dispute those findings based on they are not what I found, and particularly with the SB800 and SB900 values transposed and I only have 0.2 difference at the most.

The Canon 580EX is GN39? That puts it at GN127 ft. In my comparison, and your comparison, that would make it more powerful than a Metz 45.

Do you believe that article?? I don't..

I absolutely fail to believe the charts that the 'real' output is HIGHER than the claimed output!!!

I referred to the article because of the relative positions of the two Nikon flashes, compared to the Canon 580EX. I suspect a typpgraphical error in one chart, since the relative positions of SB800 and SB900 are reversed between the two charts.

But, per the second chart and the relative positions, the Metz 45 is on top of the chart, over the best of the other flashes by 0.5 EV, and over the Canon 580EX by more than 0.5 EV...which brings us back to my earlier statement, once again.

You do not have to believe the absolute value of the Guide Numbers, but look only the the relative ranking of the outputs to see how the units stack up to one another.

[PhotographersWorldWide]

Originally Posted by Wilt

I referred to the article because of the relative positions of the two Nikon flashes, compared to the Canon 580EX. I suspect a typpgraphical error in one chart, since the relative positions of SB800 and SB900 are reversed between the two charts.

But, per the second chart and the relative positions, the Metz 45 is on top of the chart, over the best of the other flashes by 0.5 EV, and over the Canon 580EX by more than 0.5 EV...which brings us back to my earlier statement, once again.

I think you do the 580EX a mis-justice based on my tests, and then even retesting again.. 0.2 would be reasonable but >0.5 seems out of the ballpark to me. Neither the SB800 nor the SB900 go anywhere near there.

I have two SB800's and just compared those together. One is 0.2 less the other at 35mm, (and weirdly displays this difference on the LCD @ 1/1).. so this levels the SB900 and SB800 taking this difference into account. In comparison to the Metz the difference at 35mm is now -0.1 for both.

You'll only know the true comparison if you measure the CT45 and EX580 together.