Olympus RC TTL mixed-flash vagaries

ctlow wrote:

Paulmorgan wrote:

Part of your problem I think is that your bouncing both units and in doing so your creating a single light source (just maybe)

Interesting thought, Paul, esp. since the mixed-flashes factor makes things, I still wonder, less quantifiable. I might have fallen into the "use-all-the-toys" trap. A single flash could probably provide the same effect - bouncing off a back wall. Let's try it. This is the more powerful (why not?) FL-50R:

The problem you having is that your not lighting for the subject, your lighting for the back wall.

Try lighting the subject instead.

522 -EC: 0

I think that the exposure I like best on a monitor is this one:

525 -EC +2.0 (!!)

It compresses easily to this:

525 -tonal compression (expansion, I suppose, more accurately), no other processing

And there was still juice in the flash - I stopped at EC +4.0 and it was still going.

The take-home for me: EC +2 stops with this specific setup, at least. That's enough EC that one could be forgiven for thinking that it just isn't going to work, and reverting to manual. And that's on a light background. And it might not apply to more direct flash ... etc.

Charles

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ctLow Photog

ctlow wrote:

Paulmorgan wrote:

The problem you having is that your not lighting for the subject, your lighting for the back wall.

Try lighting the subject instead.

Yes, I know, and am understanding that better and better.

I continue to believe that in an ideal world, indirect lighting should work and is often the light one wants.

So, having thought that the poor teddy bear could rest now, I did another short series, with direct lighting through an umbrella camera-right, using the FL-50R, and a reflector camera left, both close in.

568 -RC TTL, EC: 0

It's not exactly to my taste, but actually not bad! I went up in 0.7 stop increments, and...

570 -EC +1.3

...this is too bright. The in-between one (not shown) is marginal, although none of their histograms bleed right off the right.

These can all easily be processed to make them punchier, but for purposes of illustration, I'm just using the ("vivid") JPEGs OOC except smaller.

So, that's informative, and it does appear correct, for this particular scene at the very least, that direct (diffused) light with a single RC TTL flash (and reflector) requires less EC than indirect. Whether that's the light one wishes or not is a secondary question, but with indirect, surprisingly vigorous EC adjustments have been necessary.

Charles

See not bad, that TTL did a pretty good job in the end and with zero comp needed, all you needed to do was to properly position the flash units and light the subject.

Lighting levels is much a matter of personal taste, there is no real correct exposure unless your doing some sort of lab test.

Part of the problem that you was having is that you were using your reflector (the wall) as part of the scene and lighting it instead of the subject, the camera`s metering was trying to correct and balance for this leaving your teddy under exposed.

ctlow wrote:

Paulmorgan wrote:

See not bad, that TTL did a pretty good job in the end and with zero comp needed, all you needed to do was to properly position the flash units and light the subject.

Lighting levels is much a matter of personal taste, there is no real correct exposure unless your doing some sort of lab test.

Part of the problem that you was having is that you were using your reflector (the wall) as part of the scene and lighting it instead of the subject, the camera`s metering was trying to correct and balance for this leaving your teddy under exposed.

Almost. Although I did a variety of setups, the main one was bouncing two flashes off a wall behind me, so no it did not factor into the camera's TTL exposure. The camera is good but cannot see behind itself! (Like used to leak sometimes in the viewfinder, if much brighter than in the scene, in SLR days, and confound the exposure ... but that can't happen with mirrorless, I don't think.)

Well it did factor in as it shows, it lit the wall up behind your teddy and the camera then attempted to balance it all to 18%, the teddy ended up being under exposed.

The solution that I then suggested for you sorted it all out ie as in light the subject.

So, you've said all along that the Olympus RC TTL system works but one just needs to learn how to use it, and that's what this has been all about. Using it well has surprised me, as in on occasion needing +2.0 stops of RC TTL exposure compensation with some setups. Anecdotally, bright areas in the photo (not necessarily the subject) are particularly difficult.

Once you get your head around it you will also find that there will be occasions that will require negative comp as well.

Charles

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ctLow Photog

In the case of a rear wall being reflector the flashes would usually be where the camera is so the distance from flash->wall->subject is shorter and the shorter the better.

As Paul says, concentrate on lighting the subject directly, then worry about the rest of the room via some wall and/or ceiling bounce.

Sure, if the subject is a room full of stuff like some house for sale shot then bounce everything to flood the room with light, no deep shadowy areas anywhere.

If the subject is the bear or some central item then some umbrella/softbox aimed directly at it and add room bounce to even out the area behind. You only need to concentrate on lighting the subject and the amount of the room that is in the frame. So if only trying to light with bounce you need to be in the smallest room possible or at least have the camera and flashes close to any back wall used as an over-the-shoulder bounce surface.

I guess it all depends on whether you want a totally flat light with everything getting exactly the same amount of light from all directions, or need some contrast and modelling in the subject and scene by making the light a bit more directional.

As for having to work flash compensation up and down, yes, that is nearly always the case. The Oly flash TTL metering is very sensitive to placement of objects in the scene.

Assuming flash on or near camera and direct and/or ceiling bounce: If all you need in the frame is at the same distance from the camera it's easy, if some closer reflective thing intrudes into the frame then the metering favours the close thing thus the close thing is exposed properly and then your subject further back is under-exposed.

Try to shoot say a bunch of family all standing back a few meters from the camera, all goes fine, if an errant child gets closer and pops their head in the frame at say half the distance to the group, then the child's head will be OK and the rest in the dark.

So arranging the scene that appears in the frame combined with trial and error flash compensation is always needed.

If you have indeed managed to flood the room evenly with light from bouncing in all directions then that closer subject intruding in the frame of course is getting the same light as the more distant subjects so all is evenly lit and all is good. But there still could be flash compensation needed.

It's all experiments when dealing with flash, and the more tricky and weird the flash setup and aiming then the more unknowns creep in.

The primary concern as I see it is first getting the subject lit in the way desired, then secondly worry about the rest of the room.

Regards.... Guy

ctlow wrote:

http://photographio.com/cover-viewfinder-long-exposures/

But I do not know his qualifications.

-from https://www.flickr.com/groups/1949459@N23/discuss/72157645343508265/:

"...the only real way to remove this issue is to get rid of the reflex mirror and use a EVF ..."

Again: qualifications?

-from https://www.dpreview.com/forums/thread/3501933:

"With you NEX-6 there is optical path from the viewfinder to the sensor. Since the finder is electronic there is no way light getting into the finder will fog your images."

I don't know who he is either.

Nonetheless, 100% congruence. I cannot find a contrarian on this. I agree with the observation that rear-bounce lighting may underexpose in Oly RC TTL, vs. direct lighting, but not with the viewfinder light-leak explanation. I just think it likely that the Oly RC TTL system is amazing technologically, but has limitations. My bright-background, rear-bounce setup is really pushing it beyond its design parameters.

Olympus of course hasn't documented that anywhere.

Here is the setup, not the only one I experimented with, but the most problematic one:

Teddy Bear Olympus RC TTL rear wall/ceiling diffuse bounce lighting setup -ctLow

I'm not judging Olympus - very happy user of their products for over 40 years now. It just cannot do this properly, "properly" meaning without major exposure-control adjustments.

Charles

Well I`m not to sure how covering your viewfinder is going to help, the shutter is only open for a very short duration (usually) when using flash.

As for rear bounce lighting, the only times I can think of it under exposing is either with the flash running out of juice and there is just not enough power left (rare) or if there are other elements in the scene that are going to effect the TTL (common)

In your scenario its pretty clear what is going on, the wall behind that teddy got lit up like a Christmas tree, the TTL tried to compensate for this which it has but its left that teddy under exposed.

For that TTL metering probably 99% of that reflected light used for that exposure came from that rear wall.

The shot you then took using flash to light the teddy (teddy) as I later suggested worked and look at the white background its almost gone.

The flash, it has exposed for the subject and the inverse square law shows you what the flash was doing (subject well lit by TTL, background now pretty dark)

And it looks like an enormous amount of power is being wasted with that flash layout.

Bring the whole lot closer to the wall currently used as a reflector, put the subject closer to one wall on left or right as reflector, place one flash on opposite side as main light and use other flash to light background.

OzRay wrote:

And it looks like an enormous amount of power is being wasted with that flash layout.

Bring the whole lot closer to the wall currently used as a reflector, put the subject closer to one wall on left or right as reflector, place one flash on opposite side as main light and use other flash to light background.

Yes, its wasting a whole lot of power and its turning two sources of light into a single light source creating very flat lighting.

Usually we add a second light as a compliment to the first, the first becomes our main our second becomes our fill, background light, hair light etc etc.

Lighting, it a bit like cooking a meal,  it needs of plan, it needs a recipe and it also needs some flavour.

Paulmorgan wrote:

OzRay wrote:

And it looks like an enormous amount of power is being wasted with that flash layout.

Bring the whole lot closer to the wall currently used as a reflector, put the subject closer to one wall on left or right as reflector, place one flash on opposite side as main light and use other flash to light background.

Yes, its wasting a whole lot of power and its turning two sources of light into a single light source creating very flat lighting.

Usually we add a second light as a compliment to the first, the first becomes our main our second becomes our fill, background light, hair light etc etc.

Lighting, it a bit like cooking a meal, it needs of plan, it needs a recipe and it also needs some flavour.

Indeed. If you only have two lights and need to light a subject and background, then reflectors to bounce the main light (or a window) has always been the go.

That's what I've been trying to suggest in a number of posts. Use one light first as a main, look at the result, then add fill by whatever means until a balance is achieved, and then work on the background.

One step at a time. Once you understand this, it becomes almost intuitive.

OzRay wrote:

Paulmorgan wrote:

OzRay wrote:

And it looks like an enormous amount of power is being wasted with that flash layout.

Bring the whole lot closer to the wall currently used as a reflector, put the subject closer to one wall on left or right as reflector, place one flash on opposite side as main light and use other flash to light background.

Yes, its wasting a whole lot of power and its turning two sources of light into a single light source creating very flat lighting.

You can do one heck of a lot with just a few reflectors and a single liht, I just love this one

https://www.youtube.com/watch?v=F9gVQFhCXEQ

Usually we add a second light as a compliment to the first, the first becomes our main our second becomes our fill, background light, hair light etc etc.

Lighting, it a bit like cooking a meal, it needs of plan, it needs a recipe and it also needs some flavour.

Indeed. If you only have two lights and need to light a subject and background, then reflectors to bounce the main light (or a window) has always been the go.

That's what I've been trying to suggest in a number of posts. Use one light first as a main, look at the result, then add fill by whatever means until a balance is achieved, and then work on the background.

One step at a time. Once you understand this, it becomes almost intuitive.

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Thoughts, Musings, Ideas and Images from South Gippsland
http://australianimage.com.au

I remember when I first started my photography course (1976?), one of our first sessions involved a camera, one light, an egg and a piece of coal on a background of your choice. The aim was to produce a result that showed the shape and texture of the egg and the coal.

Often less is more.

OzRay wrote:

I remember when I first started my photography course (1976?), one of our first sessions involved a camera, one light, an egg and a piece of coal on a background of your choice. The aim was to produce a result that showed the shape and texture of the egg and the coal.

Often less is more.

I can remember doing stuff like that myself

I then got into buying all the womans glossy fashion magazines and spending hours trying to suss out and learn how each shot had been taken, I very rarely got an exact lighting match but it was during that period that I probably learned the most about lighting, mostly through trial and error.

Back then it was all film, there was no internet, photography mags were crap (probably still are) and most portrait/lighting books were decades out of date