Why WOULDN'T camera companies offer flash control like this?

Every time I read an article like this:<br>

http://www.shootsmarter.com/infocenter/jt024.htm<br>

I come back to the same thought about various camera companies' flash

offerings. Flash output seems to be dependent on:<br>

1) aperture of camera<br>

2) distance from subject<br>

3) photographer's taste<br>

What I can't understand is camera manufacturers have the ability to

implement this system with the introduction of distance reporting AF

lenses so why don't they set up a flash mode as follows:<br>

Point 1 requires the flash to extract the aperture from the camera

automatically (easy)<br>

Point 2 requires the distance to the focussed subject which Canon and

Nikon and probably others are rolling out across their lens

offerings<br>

Point 3 put a slider on the back of the flash so the photographer can

adjust to taste. If its at 0, the flash matches ambient, at -1.5 it

underexposes by 1.5 stops for a nice fill, etc.<br>

This is the method that the Al Kaplan's of this world have used in

manual form for years with great results, but with a touch of

automation passing data from camera to flash. It means you are not

second guessing what your flash system is going to do, and it is

consistent. It doesn't mean that Canon have to toss out all their

xTTL automation for the beginners, but I can't udnerstand why they

wouldn't add this in to give control and therefore consistency back

to the photographer?

Perhaps Im missing something, but isn't this flash exposure compensation?

...but based on what? A 400 line piece of computer code taking into account reflectivity of shiny surfaces with and without flash, segmentation of viewfinder, averaging segments, trying to get the scene to 18% grey, or some other 'intelligent' factors to hand hold users?

This post discusses something similar.

 

http://www.photo.net/bboard/q-and-a-fetch-msg?msg_id=00Clwo

 

Thing is, why not just use manual? The manufacturers need to make the physical flash controls easier to use instead of having to go through layers of menus, etc. As I mentioned in the post I sited, I thought Gary Fong was working on something like this, and it hasn't materialized, so there must be some reason?

Using distance to calculate flash has been going on for years. If you have the time you can look at your lenses distance scale, locate the distance on your trusty Vivitar 285s calculator dial and then select the power level that will give you the aperture that you want. In all of the testing that I have done, this is the most accurate way to use on camera flash. However it is also one of the slowest unless you take the time to commit the distance and power combinations to memory. This is a feat I yet to accomplish. An distance based automatic flash calculation system where the users selects the aperture and the lens transmits the distance to the flash allowing it to set the proper output level would be ideal. I believe that Minolta may already use a variation of this? Its kind of scary though, the ability to nail every flash exposure the first time would really put us out of business!

Nadine, that thread does raise a great negative to this system with bounce flash (I have no idea how people used to calculate this with manual only flash systems). But I really wanna know why the manufacturers wouldn't offer this. They wouldn't even need to retool teh plastic casing of a 580ex, just use the jog wheel as the slider. You flick the flash over to this distance mode if the lens has distance data capability and the only control you then need is the jog wheel for flash comp. All they need is to implement this in firmware, what am I missing?<br>

Todd, that's exactly what I'm talking about, just get the camera to pass aperture and distance info to the flash and compensate to taste.

distance-based flash exposure is a fantastic idea. if I recall, the same function was on the s3 yashica rangefinder or something like that 30 or more YEARS ago...

Actually, Nikon, Canon, Pentax, and probably a few other companies have been incorporating distance info from the lens into flash calculation for some years now.

 

Unfortunately, it's not all that simple. We would like to think that when a flash capacitor sends a certain amount of power to the flashtube, the exposure would remain consistent, but it does not.

 

Beyond your numbers 1, 2, and 3, there are the characteristics of the location and subject failure to take into account. Believe it or not, most flash calculations are designed for a common white-ceilinged room. Take the flash out of doors where with no white walls or ceiling to reverberate off of (and fill in some shadows), and your exposure can drop by as much as a stop from the rated maximum power. Take a picture of a Newfie (Newfoundland breed dog, totally black) under those circumstances, and you might require several more stops, as those puppies suck up light like a sponge (that's known as "subject failure").

 

Pop your flash just after your ready light comes on, and you may only get 80% of the rated power. If your flash is older, the plastic lens can be darkened by ozone buildup by as much as a stop or even more. Capacitor breakdown can do the same thing.

 

About the only way to completely overcome these problems is with a manual flash spot-meter, which of course is cumbersome, but I sure do wish they'd build one into a camera.

 

Happy shooting. -BC-

The old rule of thumb for bounce flash with manual flash setting is estimate the distance the light has to travel ~ flash to ceiling to subject, divide into the guide number, and then open up one to two stops depending on proximity to other reflecting surfaces such as light colored walls.

 

A fair number of cameras in the 60's and 70's had a setting where the aperture could couple to the focussing to change the f-stop depending upon distance, so a manual flash would give consistant exposure. With things like white dresses and black tuxedos this will give you better exposures most of the time than the fanciest TTL camera or auto-thyristor flash unit.

 

Of course manual flash was a lot simpler back when B&W was ISO 400 Tri-X and ISO 160 VPS was the only wedding and portrait color film, You rarely shot both on the same job. Now everybody wants to use a bunch of different film speeds. No wonder it's confusing!

 

Rather than change f-stops some of us used to regulate the output of our 2 piece (seperate power pack) flashes by covering the front of the flash head with our spread out fingers. The closer together the fingers are the less light gets through. Spread wide cuts one stop, a bit closer cuts two stops, closer still three stops. You knew when regulating it that way that going from a group shot to a couple was a one stop difference. Another stop for a 3/4 shot. Another stop for a head and shoulders of one or two people. Still another for a tight shot of the hands with rings posed on the bouquet.

 

5.6, 8, 11, 16 and 22. Simple! No deep thinking required! Many photographers taped a "cheat sheet" on the back of the flash! When Vivitar first came out with the 283 about 30 years ago none of us trusted the things. After a few years of looking down at the "amateur junk" we gradually came around. I have two of them, and two of the smaller 2500 model. They're 100% trustworthy, but they can't think, only react. We can think! Sometimes switching to manual makes sense. At least for awhile try sticking to just one ISO, one flash model, until you don't have to think anymore. You'll just do it! It can be so liberating.

Bill, the light sponge of a dog is just like a black tux(probably worse) or a white dress where you shift the slider to compensate. You know you need 2 stops more so you push the slider. I guess the simplest way I can think of to overcome any degradation in the plastic or flash capacity over a long period is to have a calibration setting where you stand in front of a mirror at 3 feet and fire the flash. It senses how much actual power came out of the front and adjusts itself accordingly. Thanks for the bounce flash lesson Al!

Sounds like a nice interface for an automated flash system. Can't count on the camera companies to do what is best or logical.

 

Shot at a wedding last friday night with my 550 EX and all its offerings (whooop). Lights down music up, set it to +2, aimed straight up, Tv, 1/60th and had a range of 3 stops. Best flash work I have done since getting the camera (350D) in May. I was ready to toss it two weeks ago. Only regret was not using a higher shutter speed.

Well also with digital, you have to be more precise, and a lot of the bounce calculations depended on film's latitude. I am kinda liking ETTL II now that I've played with it extensively and can more or less know what it is going to do.

You're right, Nadine, about film's latitude being more forgiving. Especially low contrast color negative film, and the best thing to do is err a bit in the direction of overexposure.

 

In the 1950's there was a fad of shooting stereo slides. Projection was possible, using Polaroid glasses, but was a royal pain and the projectors were extremely expensive. Most people used a hand held viewer. Film was mostly ISO 10 (yup, TEN!)Kodachrome, an extremely contrasty and expensive film at the time. Still, people managed to get pretty consistantly good exposures without using auto anything! Sometimes you can find boxes of old Kodachromes, either stereo or regular slides, at yard sales. The color is about as close to fade proof as you can get! It's amazing what amateurs were able to accomplish with little more than the exposure guide sheet in the film box to guide them, along with maybe the flash instruction book.

Nikon has been doing all of this this for years and quite accurately too.

Al wasn't Kodachrome ASA I mean ISO 25? It definately came in a yellow can with a red lid

Well you can use manual settings.

 

OTOH, I would love to see a flash like that implemented/developed too. I imagine it will come soon enough.

Larry, Back in the fifties, Kodachrome was ASA 12. Kodachrome II which evolved into Kodachrome 25 was ASA/ISO 25. Kodachrome X became Kodachrome 64 at ASA/ISO 64

If shooting manual then you just need to wind the dial of the 580ex, if using ETTL then you wind the dial to taste, bit like you're suggesting.

 

I use a Metz 54 mz-3 (just bought another as backup to replace the 580ex) and I use it in auto mode. There is a (too) little wheel for dialing in + or - three stops and it reads the ISO, aperture and zoom setting from the camera. It's pretty accurate...

"No deep thinking required! Many photographers taped a "cheat sheet" on the back of the flash! "

 

I tried this recently with a little Nikon SB 30 flash. It's got a dial on the back for 3 manual power settings, a built in difuser that cuts exposure by about a stop and a slider that offers plus or minus .5 compensation, so there's lots of options. I taped a post it note with a spreadsheet of fstops and distances to the back of the camera. The system works like a charm, and while the sb30 doesn't have much power, it works great for providing a balance of ambient and flash with fast lenses.

Ben, I think I'm going to go that route also. Auto flash seems like it would be a pretty

simple path to consistency for digital flash control where filters aren't used as much. Are

you finding that to be true?

Ben, I've read quite a few of your posts as you went through the flash purchasing cycle. I'm about to try a Nikon SB80 in auto on my Canon 20D and see how that works out. If the flash could pick up distance data from the body, its seems to me that it wouldn't really need to rely on its own light sensor. Did you find that the 580ex was consistent if the camera was in manual, but because you wanna shoot in Av or Tv you chose the Metz?

Well folks, I do know that Kodachrome, the original version, was variously rated at 8 and 10 but I'm not sure about 12. Films were rated in "Weston" and "GE", and those two major light meter manufacturers couldn't quite agree on which numbers to use. The British used BSI, the Germans DIN, and the Russians used GOST speeds.

Bringing a bit of order to the madness in the U.S. was the decision by everyone here to use ASA (American Standards Association). Gost numbers were double the ASA number.

 

They used to tell us that ASA (and the others) weren't directly convertible to DIN because the numbers were based on different measurement points. DIN was based on the amount of exposure required to achieve a given density above the base fog level of the film. ASA was calculated by the straight line portion of the "H&D curve". In the early days of ISO it was decided it really didn't matter all that much! The original ISO number included both the old ASA and DIN numbers such as ISO 100/21. After a few years the DIN part was dropped.

 

Yup, back before computers and Photoshop started clogging up photographers' bio-analog storage capacity between their ears they were just kind of expected to learn all that stuff. It appeared in basic how-to books and was endlessly discussed in photo magazines. The result was most people could get maybe 30 decent exposures out of 36 on slow contrasty slide film even if they only dug out the camera for holidays, special occasions and a week in the summer. This is progress?

All of my "old" 1970s vintage consumer grade fixed lens rangefinders have had some form of distance based flash system, whether as part of a dedicated camera/flash system (Canonets) or linked to the flash guide number being set on a camera dial.

 

These worked pretty well, before auto-thyrister flashes were commonly available or affordable, except when the camera tried to lock the shutter so you couldn't make a "bad" exposure. That was a PITA.

 

The only improvement I'd like to see in Nikon's CLS flash system with the SB-800/600 is to link flash output to the chosen focus bracket or zone. While it's a very good flash system when combined with a compatible camera like the D2H, D2X or D70, it's still too easy to fool in TTL mode when there are subjects in the foreground a few feet away and in the background 25 yards away.

Marc, I thought ETTL worked for you? The Metz 54 will not work in auto mode in Av or Tv mode unless you have the hotshoe flash DOWNGRADED to 3201 m1. Metz did it for free here in the UK, sent me back my check with a compliments slip!

 

Jonathan, I don't think it will work. I tried a Nikon flash in auto mode on my 10D and the exposure was spot on, but it cannot communicate with the camera at all so you have to dial in all the settings yourself.

Jonathan--what is the problem you're having with ETTL II? While I hated ETTL (the original), I sorta like ETTL II. I just shot a whole wedding with a 20D and 580EX in jpeg (don't start on that--I had to), and got really good exposures, both with and without the flash. The wedding started in the mid-afternoon and went into the evening, outdoors in sunlight, shade (both light and deep) and outdoors at night. I left the flash in evaluative mode and used both manual settings and AV, using various combinations of minus/plus ambient and flash exposure compensation. They all came out well, even the ones where I was shooting fast and couldn't re-shoot if I wanted to. I was plesantly surprised. I didn't think it could be done.