Nick D. Posted December 23, 2018 Share Posted December 23, 2018 Just got 2 almost new Cameron W700HS TTL-N for $40 each, love them:) Link to comment Share on other sites More sharing options...
rodeo_joe1 Posted December 23, 2018 Share Posted December 23, 2018 Just got 2 almost new Cameron W700HS TTL-N for $40 each, love them:) - OK, but I don't see how that has any relevance to this thread. Having never heard of 'Cameron'; who really makes them? Unfortunately it looks identical to the awful Meike SB-900 clone I bought, which was my worst flash purchase ever! Link to comment Share on other sites More sharing options...
Nick D. Posted December 23, 2018 Share Posted December 23, 2018 It works for me, why bother with GN if you can get TTl for pennies. Link to comment Share on other sites More sharing options...
paco_rosso Posted December 23, 2018 Share Posted December 23, 2018 No! ¿Why? Link to comment Share on other sites More sharing options...
rodeo_joe1 Posted December 24, 2018 Share Posted December 24, 2018 It works for me - Oh, the Meike worked. It was just nowhere near as powerful as claimed. Barely any improvement on the popup flash in the camera. why bother with GN if you can get TTl for pennies. - Or why bother with TTL when you can get used Auto Aperture flashes for even less? Link to comment Share on other sites More sharing options...
BeBu Lamar Posted December 24, 2018 Author Share Posted December 24, 2018 ¿Why? I want it to set the aperture of the lens automatically. Link to comment Share on other sites More sharing options...
hjoseph7 Posted January 14, 2019 Share Posted January 14, 2019 Something like this? Link Understanding Camera Flash Guide Numbers, plus GN Calculator Thank you Sandy now I can prepare a handy Flash chart(ISO, F number, distance) for my speed light when i decide to use it in manual mode ! Link to comment Share on other sites More sharing options...
rodeo_joe1 Posted January 14, 2019 Share Posted January 14, 2019 Thank you Sandy now I can prepare a handy Flash chart(ISO, F number, distance) for my speed light when i decide to use it in manual mode ! - If you start with the speedlight maker's own guide numbers, be prepared for some very underexposed results! I don't know how they've got away with it for years, but every single published GN is optimistic by about one stop - and maybe a lot more at the long 'zoom' end of the flash. Do yourself a favour and divide all the stupidly-inflated published guide numbers by about 1.3, then you'll be somewhere in the right ball park for a correct exposure. For example: the manual says GN 36 (metres), that'll be closer to 28 in reality. There is no speedlight made that reaches anything like the claimed GN of 58 that I see widely (and wildly) advertised. :mad: Link to comment Share on other sites More sharing options...
hjoseph7 Posted January 16, 2019 Share Posted January 16, 2019 The guide numbers use to work fine with those little charts on the back of flash units prior to thryistor technology (Automatic). Flash manufacturers had to base their calculations on something. Link to comment Share on other sites More sharing options...
hjoseph7 Posted January 16, 2019 Share Posted January 16, 2019 I know that famous wedding photographers like Steve Stint use the guide number. Sure its not perfect, but its something, otherwise we are talking about trial and error for every single flash unit on the market . Link to comment Share on other sites More sharing options...
rodeo_joe1 Posted January 16, 2019 Share Posted January 16, 2019 (edited) I know that famous wedding photographers like Steve Stint use the guide number. Sure its not perfect, but its something, otherwise we are talking about trial and error for every single flash unit on the market . - Sure, guide numbers work once you've established the correct one, by, as you say, trial and error, or flashmeter, or chimping with a digital camera. All I'm saying is that makers' guide numbers are basically a pack of lies to make their speedlights (lites) appear more powerful than they really are. Once one maker got away with it, the rest followed. Also the 'zoom' increase of guide number is nowhere near as great as is claimed. No professional trusts those published guide numbers without doing their own testing. Although I've found that Auto Aperture mode is generally accurate, while manual setting according to published guide numbers definitely isn't. In short; using the flash makers' guide numbers will almost certainly give you underexposure. And more so if it's a cheap make like Hanimex, Cobra or suchlike. Edited January 16, 2019 by rodeo_joe|1 Link to comment Share on other sites More sharing options...
rodeo_joe1 Posted January 16, 2019 Share Posted January 16, 2019 The guide numbers use to work fine with those little charts on the back of flash units - I doubt they ever did. The underexposure probably went unnoticed back when the latitude of negative film covered it up. Link to comment Share on other sites More sharing options...
hjoseph7 Posted January 16, 2019 Share Posted January 16, 2019 (edited) - I doubt they ever did. The underexposure probably went unnoticed back when the latitude of negative film covered it up. Notice that they call it "Guide Number" not Absolute or Finite number or anything like that. I usually check all my flashes with a flash-meter to determine how close they are to the stated "Guide Number", especially if I purchased the flash used. Battery power can also influence the Guide Number. If your batteries are weak the Guide number goes down. In the field I will use the FEC accordingly. Edited January 16, 2019 by hjoseph7 Link to comment Share on other sites More sharing options...
rodeo_joe1 Posted January 16, 2019 Share Posted January 16, 2019 (edited) Notice that they call it "Guide Number" not Absolute or Finite number or anything like that. - Indeed! But it still catches the unwary by surprise when their new and expensive 'GN 58' flash turns out to be no such thing. The old 1970s ISO standard for reporting Guide Numbers used to have some vague wording like - 'Giving a minimum useable exposure' or some such useless guff. I'd kind of hoped they'd tightened the specification in the intervening revisions, but it appears not. It's not like it's a difficult or expensive thing these days to actually measure the output of a flash under fairly standardised conditions. And it's time that we saw independent testers doing just that and blowing apart the makers' inflated GN claims. Also time that the ISO made their 1230 'specification' worth something. Because it's certainly not worth the 38 Swiss Francs they're asking for it now! Edited January 16, 2019 by rodeo_joe|1 Link to comment Share on other sites More sharing options...
hjoseph7 Posted January 19, 2019 Share Posted January 19, 2019 Here is an interesting article about the True GN for the Canon 580EX and 430EX. Maybe this guy saved me a whole lot of work... The real guide numbers for the Canon 580EX II and 430 EX | Strobist.com | Flickr Link to comment Share on other sites More sharing options...
rodeo_joe1 Posted January 20, 2019 Share Posted January 20, 2019 (edited) Here is an interesting article about the True GN for the Canon 580EX and 430EX. Maybe this guy saved me a whole lot of work... - And yet you wouldn't believe me half-a-dozen posts ago; when I told you that all makers' Guide Numbers are inflated by about one stop. I've tested* dozens of hotshoe and hammerhead flashes from all the major manufacturers - and some obscure ones - and if you knock a stop off the published guide number you won't be far from the truth. *Using 3 different flashmeters that all agree with each other to within a tiny fraction of a stop, and taking verifying exposures using a variety of digital cameras. WRT using multiple flashes by guide number: If you add the (true) guide numbers and then divide by 1.4 you won't be far off - provided the flashes are at the same distance and used direct. However, that wouldn't usually be a very aesthetically pleasing lighting setup. Edited January 20, 2019 by rodeo_joe|1 Link to comment Share on other sites More sharing options...
stuart_pratt Posted January 20, 2019 Share Posted January 20, 2019 Who of us wants to drive a stick shift with clutch car? Only those who reminisce, but when you get a sprained knee, you wish you had an automatic transmission. 90% of Brits, that’s who! Link to comment Share on other sites More sharing options...
rodeo_joe1 Posted January 21, 2019 Share Posted January 21, 2019 Who of us wants to drive a stick shift with clutch car? - You mean there are other types!? Link to comment Share on other sites More sharing options...
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