Myth busting the Ratio flash debate

[bfitzgerald]

It's been suggested from various sources that it's not possible to provide the old ratio flash as per previous models such as the film 5 and 7. This was using the on-board unit to provide 1/3 of the power and the off camera wireless flash the other 2/3 of the output.
The reasons I have read were because it's digital and not film metering limitations etc etc

I have questioned this logic as it was a body function which was removed by Minolta from the last 2 film bodies they products (60 and 40) neither can do ratio wireless (40 can't do wireless at all if I remember correctly) It was not as some said removed on the 5/7d models it started with the last 2 35mm ones

Since this time I have discovered that this function is available on K mount bodies (called contrast control) and you can do the old wireless ratio flash across the entire current range as erm these are digital SLR's and you have the exact same set-up (on-board and dedicated unit for wireless) I therefore declare the misinformation about "digital can't do ratio flash" as incorrect.
I note the new HVL-F43AM still does not offer ratio flash for non A850/A900/A700 users this is because it's not been re-instated as a body function not because digital bodies cannot perform this task.

I find the ratio control quite useful as normal bounce can be a tad flat. Let's hope Gary updates his site soon

[David Kilpatrick]

Same with the Nissin i866 - it has all the wireless and ratio functions, but the moment you fit it to an A55, A580, or anything except an A900/850 or A700 the function just switches back to plain TTL. Can't do wireless ass a commander.

What's interesting about the Nissin is that in commander mode, it can manage to trigger remote wireless flash without a trace of exposure from the on-camera unit.

David

[bfitzgerald]

I've not had many problems with the on board turning up in the final shot but I know some have maybe it's because I rarely use it at close range.
Also heard of some compatibility issues with film bodies and some of the newer flashes.

Back to ratio flash whilst it's not a "big feature" it is something that could be re-instated to bodies..I was never a fan of the strategy to only allow full functionality with the FF bodies.

[Greg Beetham]

A bit of conjecture, maybe DK can help out.
I sortof got the impression the extinction of RATIO was more to do with TTL-OTF not being available in digital for fine tuning the flash exposure, they never figured out how to do an equivalent OTS. I remember reading a long time ago that the exposure in film cameras could be regulated via the OTF during the exposure with manipulating the shutter (early closure) and the stepless f-stop feature. But I have noticed that the A700 can auto regulate the flash exposure (maybe more to do with sensor gain and quenching than with the shutter and lens manipulation, or a combination of all) via TTL during the flash exposure (also the KM5D and A100 can do it) even if the external flashes aren’t under the command of the camera using old non digital flashes that have their own settable onboard exposure control on separate stands triggered by a light sensitive slave trigger, you can’t use the popup for that though, too many pre-flashes using the popup, one must use a system flash and set the camera settings accordingly. I know my 3600HSD and F56 both can be made to work to trigger the external flashes on cue, and that may in turn depend on using a trigger that is not sensitive enough to trigger on any small remaining pre-flash. Of course that isn’t an issue with the A900 it doesn’t even have a popup flash.
So if those cameras can regulate/fine tune the exposure internally (on the fly) of flashes not directly under the control of the camera it is rather peculiar that they decided to scrap the RATIO feature in some camera and flash models…maybe they figured it wasn’t such a great feature after all, not when you can duplicate it’s effect reasonably easily yourself.
Greg

[David Kilpatrick]

Ratio control is not a big issue if you own two different guns, such as the HVL 58 and 42, because this automatically provides ratio - almost a clean 2:1 between the guns. By using a set of varied flash units, you can easily achieve the most common required ratios.

It's important when using a set of identical flashguns such as HVL 58s. All TTL control was made impossible by digital, because it is not possible to use the sensor itself, and any cells aimed at the sensor don't see a surface which integrates light the way film used to. There was always an issue with film anyway, ignored by the makers, in that different films produced different flash exposure because the colour and density of the visible unexposed emulsion varied greatly.

Ratio control now is controlled by preflash and pre-setting of each head from that reading. It can be used of course to overcome the power differences between flash units, but you still can't do it with basic level flash units. The new HVL-F43AM is the first lower level flash which is fully channel, group and power controllable when mixed with HVL-F58AM.

Eventually, I see Sony leaving behind the old range - of which the 42 is the last example - completely. Ratio, group and channel control should be possible with all models in the future range. But probably not with basic entry level bodies.

David

[Greg Beetham]

I'm assuming David that when you said 'all TTL' you were referring to the OTF part of it, as all my DSLR's are using TTL in some form or another and the ADI system as well if the flash is direct from the camera.
Greg

[David Kilpatrick]

Of course, preflash is through the lens (hence Pre-Flash TTL) but ADI is not, it is a safety net designed to stop TTL errors. What I meant was real-time TTL - quench metering. Pre-flash TTL is not the same kind of TTL as TTL-OTF, or even the same kind of auto exposure as thyristor.

For one thing, the full power of the flash is never used. Pre-flash TTL is firing a very weak measuring burst, and by definition, it's never going to be able to do what full TTL (during the exposure, by any means, whether off the film or using a different method) can do - especially for very distant or dark subjects.

David

[Javelin]

I wonder if they could monitor a few pixels or groups of pixels here and there to preform the same function as the OTF sensor did?.

There ya go Sony... change all the flases and protpocols again!!

[Greg Beetham]

I know what your saying David, the OTF sensor is as dead as the dodo. But try a few tests in A mode spot metering with the A900 (you don’t have an A700 I think) with an independent flash that can be set to any exposure and see what happens. I was using a system flash to trigger the independent flash, and if I remember correctly the on camera flash wasn’t even aimed at the subject for some shots. I forgot to switch the camera to M mode, (until the penny dropped that is) and got pretty much the same result, a fairly decent exposure, (but I wanted a slight over exposure in one area to get rid of a pesky shadow) irregardless of what exposure setting (ISO, f-stop) was on the independent flash, and that too me is proof that the camera was regulating the exposure (somehow) internally on the fly, I can't see how it could be otherwise....so far.
Greg

[bfitzgerald]

Just to update this thread. As I'm now playing with the CLS on Nikon I can of course confirm you can do ratio flash with this system including the on-board as part of the final exposure (or not) the difference this time around is you have more groups, can specify the output of the groups (separately) and have a fine control over them exposure wise. You can also vary the output of the master flash (or onboard) so that you are not stuck with the "fixed" ratio.

On researching some flashes I've found a few with "sub flashes" too (Metz and Nissin) this solves the "flat looking" bounce shot problem though you could reduce that issue by using a white card reflecting some light directly at the subject. But useful to have this.

Flash Value (FV) Lock is another interesting talking point
Let's hope Gary drops in and updates his site soon

[twm47099]

Before the Maxxum/Dynax 7, Minolta had "Old Fashioned" wireless that they introduced with the xi series cameras. "OF" wireless is limited to 1/60 sec shutter speed (and I think 1/45 in ratio mode on older cameras, but 1/60 on the Maxxum 7).

The Maxxum 7 can also use "new" wireless up to normal max sync speed (1/200 sec) and HSS wireless up to the max shutter speed of the camera (1/8000 sec). "New" wireless and HSS wireless require using one of the HSD flashes (3600 HSD or 5600 HSD) but are not capable of "ratio" wireless (max shutter speed drops to 1/60 sec).

The Maxxum 5 could also use both "OF" and new wireless, but OF wireless was limited to 1/45 sec shutter speed in either ratio or non ratio. With the HSD flashes it could use normal wireless up to 1/125 sec and HSS wireless up to the max camera shutter speed of 1/4000.

If an older wireless capable flash was used (3500xi, 5400xi, or 5400HS) both cameras had to use the slower shutter speed of OF wireless (and set this automatically if the old flash was mounted on the camera when wireless was selected).

Since non HSD flashes couldn't be used with the digital cameras, there was no reason to have both OF and new wireless, so they removed OF (with its shortcoming of a very low maximum shutter speed). Unfortunately, that also removed ratio wireless controlled by the pop-up flash.

tom

[twm47099]

I've also noticed many more complaints about the pop-up flash trigger contributing to the exposure than I did with the older cameras. Then it was usually a complaint about a second highlight on a reflective surface or when shooting close up.

But recently on dpreview and dyxum there are discussions of normal range shots with pop-up contribution. One user actually covered the remote flash and showed the effect of the popup. I also noticed that the newer camera manuals no longer say that the popup contributes an insignificant amount of light, like they used to.

I wonder if Sony hasn't added some sort of ratio back to the cameras as the standard "normal" wireless, or just increased the power of the control flash to improve reliability.

When the camera uses HSS wireless, there is no contribution from the pop-up visible, which makes sense.

tom

[bfitzgerald]

I can't say I noticed the built in flash adding to the exposure on the 5d, but maybe it's something that does not show up for most everyday scenarios.
Minolta at the time were ahead of the game with the wireless flash, albeit with some limitations at the time (ie no HSS, added later)
The problem was it did not get developed to the extent it should have thus other makers caught up and went a bit further.

I'm not really up to speed on the A77 as to where that stands for ratio flash with multiple units. As far as I can remember to do ratio you have to get a HVL-F58AM flash.
Obviously the disadvantage is that you have to buy the top end flashgun to do this. Where as this option is available even with a built in unit on older film bodies.

[twm47099]

I can't say I noticed the built in flash adding to the exposure on the 5d, but maybe it's something that does not show up for most everyday scenarios.
Minolta at the time were ahead of the game with the wireless flash, albeit with some limitations at the time (ie no HSS, added later)
The problem was it did not get developed to the extent it should have thus other makers caught up and went a bit further.

I'm not really up to speed on the A77 as to where that stands for ratio flash with multiple units. As far as I can remember to do ratio you have to get a HVL-F58AM flash.
Obviously the disadvantage is that you have to buy the top end flashgun to do this. Where as this option is available even with a built in unit on older film bodies.

I don't know if the Minolta wireless was limited by the approach they had taken, or if they just felt it was good enough, but the other companies certainly did significantly improve on it. At the end of the film era, the big Minolta advantage was that it was standard at almost every camera level and used the built in flash as controller.

The new Sony wireless ratio using the 58 flash gun as controller is a significant improvement over Minolta ratio wireless (using the pop-up flash as controller) since the only Minolta ratio possible with the pop-up was 2:1 remote:popup. The 58 allows more groups. However, I really wish (unfortunately, I should trade mark those 3 words when I talk about Sony), that they had released (or would release) a wireless ratio controller similar to the old Minolta wireless, that had a small form factor like a compact flash, emitted an invisible IR signal but had the capability of ratio control as the 58 does. Without the 58 guide number flash tube and internals, it should be a lot less expensive, be much more portable, and not contribute any light to the exposure. But for some reason, Sony doesn't seem to get it.

tom

[bfitzgerald]

Having picked up a Metz 50AF-1 there is now a very obvious workaround for ratio flash. Simply put the flashes into "servo mode" manual and adjust flash power as required. For this unit it goes down to 1/128 power which is very decent. Couple of these flashes and I think you're good to go..or add a Yongnuo as a dumb slave too. Of course you have to set the flashes how you want power output.

Loving the Metz though it even has pre-flash suppression so I've been using it with a compact camera for product shots (ie auction site sales etc) works a treat. And you could use it with other brands as a manual slave/servo flash. Great stuff