Lighting setup..

What would be the best way to use a Speedlight for macro photography? I currently have it on a flip bracket with a ball head on it so I can have a range of motion to the flash. I also have a softbox-style diffuser for the flash. I do not want to have to get a dedicated flash for macro just yet, so I would like to work with what I got.

The main issue is, without a diffuser, hot spots and hard shadows. With diffuser comes out better, but can be a little dark. I was trying TTL so as to not mess with the flash settings much, but I am assuming manual power settings will be the way to go there (which is how I normally use my flash).

I guess I am looking for a better way to diffuse my light.

Hi,

Everyone has a frankenstein rig for macro flash. The key is the diffuser so that the apparent size of the light source is huge relative to the subject so you don't get hard spectral highlights. If you use too thick of material and do it too far away from subject, your flash may seem dim, especially as you stop down focal-ratio for depth of field purposes. Just use ISO and drag the shutter to bring ambient back up if you need to. Maybe try not to use TTL and just use manual and look to use 1/2 or 1/4 power for recycle time and more flashes. The exposure is going to be relatively constant if you are setting it for a relatively effective distance based on how close you are to focus on things for example and the only changing exposure will commonly be ambient (which I then control with ISO or drag my shutter to increase ambient as needed). I primarily expose the subject with focal-ratio + flash and will adjust as needed if I change my ISO.

I use a basic styrophoam tray and tape it onto my flash and lens hood like this. I use my flash as manual usually and keep my focal-ratio the same (so F8 or F11) for depth of field. If I raise ISO I drop my flash output by the same number of stops. Shutter speed I synch at max if I want less ambient, or I drag the shutter (slower) to let in more ambient, neither of which will effect flash exposure.

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Imagine your lens is the center of a clock face. I would put the flash inside the sofbox and position it about 2 o'clock on the clock face, aimed at the subject and closer to the subject than the camera body. Off to one side it provides some 'modelling' of the subject rather than providing flat lighting which gives the viewer no idea of the texture/surface/3Dshap​e.

Unfortunately, nTTL flash metering was not well designed for flash use inside softboxes, which is why things may not seem properly exposed! Many years ago a number of us found that eTTL flash with a softbox in front of the flash had inconsistent exposure results. There were threads on POTN about the inability of the eTTL to properly meter and command an amount of light from the flash when softboxes are put on the eTTL flash...in spite of the fact that the 580EX can properly bounce flash with eTTL exposure done properly!

I have not repeated eTTL flash with softbox testing, using more current Canon bodies than what we had 10-15 years ago.

So I would be cautious and evaluate your results at home before using it for real on real subjects to make photos that mattered to you.
I would experiment at home and find an FEC setting to use that gives closer to 'proper exposure'.

I am finding TTL works only sometimes for macro. I will leave that for no softnox when I am taking a pic of something and I can bounce it off the ceiling.

I am in the process of throwing together some ideas to diffuse the light better than that little softbox. Looking at making some type of frame that I can attach to say a step-up ring and covering the fra,e with white rip-stop nylon. Make the frame say 8-12" around. and cone-shaped somewhat. That or I had a long-ago project where I had 2 mixing bows. One larger one and one smaller one where I cut the middle out for the lens to go through and in the larger bowl I cut a rectangle the size of the flash head and rigged up a bracket to hold it to the 1/4"-20 on the body. Covered the space between the bowls with rip-stop nylon. I recall it worked pretty well, but would get circular catch-lights. I would try this again, but my vision is poor and I would prob mess it all up. LOL.

I have a few other ideas to test out and see what I like. Just been doing all my testing indoors since it has been raining for what seems like forever here.

I used to love DIY stuff when I could see better. Npw I just want to get something that works so I can spend more time taking pictures while I still can.

OK, here are some shots just made with Canon 7DII with Metz 64AF-1 flash on ETTL control.
First is a shot taken at about 1.5' distance (focal plane to subject) with Manual flash with a 5"x7" softbox on the flashhead, as the control exposure.

1. ETTL flash with 5"x7" softbox, note the softer penumbra of the shadow caused by softbox usage
   
2. Ambient light autoexposed in Av
   
3. ETTL flash without softbox, note the hard edged penumbra of the shadow caused by lack of modifier
   

Wilt wrote in post #19255970
OK, here are some shots just made with Canon 7DII with Metz 64AF-1 flash on ETTL control.
First is a shot taken at about 1.5' distance (focal plane to subject) with Manual flash with a 5"x7" softbox on the flashhead, as the control exposure.

The first shot appears to be satisfactorily exposed in Manual flash output (I set a fractional output setting); but next is the shot with ETTL-controlled flash with same softbox...considerable underexposure.

Next is a sequence at about 8.5' distance, to assess ETTL exposure accuracy with softbox and without softbox over the flash head at more usual shooting distances; ambient-only is included as the control exposure. All shots White Balanced, but no other alterations to RAW import settings.

The sequence of shots in the above triplet...

1. ETTL flash with 5"x7" softbox, note the softer penumbra of the shadow caused by softbox usage
   
2. Ambient light autoexposed in Av
   
3. ETTL flash without softbox, note the hard edged penumbra of the shadow caused by lack of modifier
   

Compare the central section of the target, which is a midtone (18% grey) with the Lightroom background density...the tonality should be about the same (see shot 1 in this post).
The #1 ETTL-flash-in-softbox shot is somewhat denser (underexposed) compared with #2 or #3
It appears that the age old assessment, published in the past on POTN, that ETTL-speedlight-in-softbox underexposes REMAINS TRUE, at least with 7DII. We need to compare with the R-mount body results.

Based upon the 1.5' distance shot results, I would start using FEC +1.66 as the minimum correction to ETTL flash in order to expose correctly (measured LR Exposure boost was +1.9EV to get mid-tone to proper density)

Interesting, and unexpected, results Wilt! The only reason I can think of for the under exposure is if you were close to full flash power without the soft box, so that the scene was under exposed with the soft box (usually they will decrease the light by at least a full stop). Due to the way that E-TTL works, by sending out a pre-flash burst to meter off of, the soft box should have no effect. Granted that pre-flash will be reduced by the soft box, but E-TTL should compensate by firing the main flash a little longer. Normally what fools E-TTL flash metering are very bright scenes (they will under expose) and very dark scenes (they will over expose) due to amount of the E-TTL pre-flash coming back into the lens. But the light meter can be fooled in the same way by natural light.

The bigger problem with using a flash for macro is the short distance between the flash and the diffusion surface that the subject sees. Most diffuser designs do not force the light from the flash to spread out, so there ends up being a hot spot in it. In a studio, with big soft boxes or umbrellas, there is plenty of room between the flash and the diffuser (or reflector) so the light across the surface of it is even. So soft light = diffused light and the only thing you have to concern yourself with is the apparent light size. But since there is not enough room between the flash and the diffuser in most field macro setups the light ends up being large relative to the subject (so the shadows are soft) and a point source (harsh specular highlights) due to that hot spot. Since the light is not diffused enough specular surfaces in the scene will act like true mirrors and reflect the color of the light source and not the color (or a shade of) the specular surface. So the light ends up erasing a lot of detail. The "trick" is to find a material that will force the light to spread out without just blocking it. I have been using several layers of 1/4 stop white China silk (a scrim fabric), with each layer separated by an air gap, and it seems to be working pretty well. I took this shot a little below 2x:

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Dalantech wrote in post #19264713
Interesting, and unexpected, results Wilt! The only reason I can think of for the under exposure is if you were close to full flash power without the soft box, so that the scene was under exposed with the soft box (usually they will decrease the light by at least a full stop). Due to the way that E-TTL works, by sending out a pre-flash burst to meter off of, the soft box should have no effect. Granted that pre-flash will be reduced by the soft box, but E-TTL should compensate by firing the main flash a little longer. Normally what fools E-TTL flash metering are very bright scenes (they will under expose) and very dark scenes (they will over expose) due to amount of the E-TTL pre-flash coming back into the lens. But the light meter can be fooled in the same way by natural light.

nTTL in softbox puzzles me, too.

1. The preflash output is diminished (let's assume -1EV for discussion only) by the softbox fabric.
   
2. The camera meters -1EV in reflected intensity (the subject distance might be 15' rather than 10', for the same decrease in return brightness without softbox),
   
3. focus distance is NOT very PRECISE (that statement based upon measurements and EXIF data examined in an experiment years ago!) so measured distance does NOT enter into any flash computations (except to know which AF zones to bias due to extra bright response like mirror surface),
   

Wilt wrote in post #19264970
nTTL in softbox puzzles me, too.

1. The preflash output is diminished (let's assume -1EV for discussion only) by the softbox fabric.
   
2. The camera meters -1EV in reflected intensity (the subject distance might be 15' rather than 10', for the same decrease in return brightness without softbox),
   
3. focus distance is NOT very PRECISE (that statement based upon measurements and EXIF data examined in an experiment years ago!) so measured distance does NOT enter into any flash computations (except to know which AF zones to bias due to extra bright response like mirror surface),
   

so one would think that nTTL would command MORE POWER to offset the reduced preflash response, and the softbox exposure should be correct...yet the test shows it is WRONG and underexposed.
In concept, this is no different than ceiling bounce flash...which nTTL gets correct!

Pertinent to point #3, https://photography-on-the.net …showthread.php?​p=18342828

Wow, that is so odd! The only issues I have run into with E-TTL flash metering is very bright, or very dark scenes, tricking the light meter into either under or over exposing (respectively). But natural light can fool the light meter in the same way, so it is not an E-TTL issue but just the way that light meters work. This morning I was shooting a relatively dark scene and had to dial in -2/3 FEC to come in a little under exposed. I prefer under exposing a scene to over exposing since more data can be recovered from shadows than from blown highlights.

Just remembered one other aspect that effects E-TTL flash metering and that is the number of metering points in the light meter. A lot of sensor's have the light meter tied to the AF points, or there are very few metering points in the frame. So when there is a lot of empty space behind the subject most of the E-TTL metering pulse goes out into empty space and never makes it back to the camera. The end result is either very inconsistent exposures, or gross over exposure. The 40D had just a few metering points, and I think that most of them were toward the center of the frame. I swore that camera had a random number generator that it used to calculate flash exposure. Most modern cameras have more metering points, over a wider area of the frame, so E-TTL flash metering is a lot more consistent. Can still get an over exposed subject if there is nothing behind it to reflect the metering pulse back into the camera but that over exposure, if it happens, will be pretty consistent. I use E-TTL flash metering for all of my macro work and I rarely run into a situation where I am forced to put the flash into manual mode.