TTL flash for macro?

[Clovishound]

I've always heard that TTL is a no-no for macro flash. I assumed that the issue was that the subject is often a fairly small percentage of the frame and the background was a relatively long distance from the subject causing the system to overexpose the subject in an attempt to average the exposure. I saw a video that advocated TTL for macro and showed some decent results. I was very skeptical, but assumed it would be easy to debunk. I went out back and shot a variety of subjects in TTL mode varying the size of the subject, distance of background, and aperture. The results were not quite as consistent as when I am in manual mode, but there were no test shots when changing subjects and no adjustments needed. All were in the envelope of relatively easy post editing correction.

Do any of you use TTL mode for macro flash? I tried it when I first got my flash with horrible results, and so abandoned it. I will have to rethink this and try some more shooting in this mode.

FYI, here are a few I shot this afternoon. All were taken directly to LR, auto settings applied with some minor exposure, texture and vignetting applied. No cropping was done. These are not intended as good images, just test shots to explore TTL. I'm not sure how much difference the camera makes in this, but I was using my new Z7ii. The first (poor results) TTL I tried a year ago were with my Z5.

This first one was the one that was off the most. My guess is that it was perhaps a stop to a stop and half overexposed.

These last two are the most telling to me. I would assume a small subject with a lot of distance to background would be the most prone to overexposure. They weren't.

This surprised me the most. I thought a white flower would raise havoc. It nailed it. I usually have to dial down the flash power when going from something like the purple flower above to a white flower.

 

[blackstar]

Thank you for sharing. I think you have got some good results from using TTL Flash. It would be nice if there were some comparisons between TTL and Manual.

 

[Clovishound]

Well, with manual flash I can nail the exposure to exactly what I want. The big difference with TTL is that I don't have to take any test shots and constantly check exposure and make adjustments when things change. This is particularly an issue when I have a good opportunity present itself, and I make a couple quick exposures and then it's gone. At that point I check my images, and sometimes there is a problem because of something like a large leaf blocking the flash, or a big change in the color of the background/surrounding foliage resulting in a badly under/over exposed image.

I shot a bunch more this afternoon, and while I might have made some minor adjustments had I been in manual mode, all were quite acceptable exposure. If you want, I could take a series of exposures, a group in manual, and a group with TTL. I could then post them without any post processing to be able to judge the difference. The biggest issue is that there may be conditions where there is little difference, and other where there is a large difference. I doubt that TTL will always give me an acceptable exposure, but it may be that it will consistently give decent to good exposure and increase the percentage of usable images due to it's ability to adjust for me in quick shot situations. Time will tell.

I may have to try a few with my Z5 and see if it gives similar results. As I said, when I first got the flash, I tried it in TTL mode with the Z5, and was NOT impressed.

 

[blackstar]

I see all the images you posted were shot by TTL, if I am not wrong that Exif shows: "

Flash Fired

Yes (Auto, return light detected)

I think there isn't any exposure issue. I assume you shot all by Manual focus? As you stated, TTL has a big advantage in that you won't waste time for test shots and increase much chance of grabbing a shot before the subject(s) move away (disappear). I think I like to go this way when acquiring a Flash.

 

[Clovishound]

Here are a few for comparison. I took a few quick shots this morning. I took a couple on manual until I got close to what I wanted judging by the image on the backscreen. I also took one with TTL setting. The manual settings were anywhere from 1/2 power to 1/8 power. I will add that, if necessary, I could use exposure compensation to fine tune the TTL exposure, if I felt it was off by a consistent amount.

In each set, the first was taken in manual mode and the second TTL. I imported them to LR and exported them to JPG format without any editing.

At this point I will probably use TTL mode for a while and see if it works well for me. I may switch back to manual for shots that I have the luxury of time to check exposure and feel some adjustments are in order.

 

[Needa]

The only one I see much difference in is the first. The TTL seem to be doing the job. With the flash you are using are is there an option to chose TTL fill as opposed to TTL? You are using matrix metering?

 

[Clovishound]

It probably does have some type of TTL fill. I remember seeing a fill flash setting in the camera menu. I've never really looked into it, as I have only been using it for macro work as my primary light source.

Yes, on matrix metering.

I do see a little more difference in exposure on the backscreen than I do on the computer, but by in large, I haven't seen any of the TTL exposures that were off by a significant amount. 2 were more than I would like, but still easily edited to good images. I still need to get the Z5 out and see if it gives similar results. Not sure how much the camera puts into the mix. Obviously, it has the sensor that the flash relies on to decide how much power to use.

Edited to add: I went out back with the Z5 and shot a handful of TTL shots. All were well exposed. Perhaps last time I tried it I had some setting wrong. It was a brand new flash, the first time out with it.

 

[BF Hammer]

I don't know. On my reduced-size displays of my phone and sub-notebook PC your TTL photos look fairly consistent in being a fraction of a stop darker. I would be just tempted to set the exposure comp 1/3 or 2/3 brighter and call it.

 

[blackstar]

(Sorry to intercept the thread) I found two vendors selling Godox TT685N II: Amz and B&H. They offer the same product and price ($129), but AMZ offers several kit versions and B&H offers a product-only version. Is any diffuser included in the AMZ kit versions useful and worth paying the tax? (B&H has tax discounted)

AMZ1

AMZ2

B&H

 

[Clovishound]

I don't consider it an intercept. This is the flash I've been using. The Amazon 2 has a small soft box. I picked up that when I first got my flash. Assuming it is the same size as mine, it works fine for macro work. Mine is 6 1/4" x 8 1/2". I prefer the homemade diffuser I put together. It is similar to the AK diffuser, although it is made of thin cardboard, duck tape and and old t shirt. It won't hold up long term, but it serves the purpose for now. There are several shoot through fabric diffusers on the market for around $10. I have one, and it works very well also. It is very convenient to use and store, and works about as well as the small soft box I have. Before I made my own diffuser, I would sometimes use the soft box in conjunction with the shoot through for extra diffusion, although I did lose some additional light power.

Most any of the diffusers will work fine to get started with. You will likely try several and settle on the one you like best. There are lots of articles and videos on the internet that go through the different types and show examples using them.

 

[Clovishound]

OK, I'm now up for the Dummy of the Week award. I discovered this afternoon that somehow my flash was in an exposure compensation mode. I've not used the flash in TTL except for the one shoot when I first got it, until a couple days ago. I wasn't really paying attention to all the information on the screen of the flash, or bother to read the instruction manual on TTL. It was only for a -1/3 of a stop, but after resetting it to 0, things look better. Here is one of a handful I shot a few moments ago to test it out. This image was converted to a smaller JPG without any editing. It is still a tad on the dark side, as were the others, but it is pretty close to ideal IMO. I discovered if you put a TTL exposure compensation value in the flash, it stays. Even if you turn the flash off, it still remains when you fire it back up. Flash exposure compensation goes away when you turn the camera off, unless you safe the settings to one of the "user defined modes". Something to consider, if I feel that it needs some constant compensation. Judging by what I see from these handful, I think it is close enough.

Here is the same image, cropped and edited, with no Topaz help.

And another a little closer up. Boy these guys really love the thistles. Those are volunteer, and not part of the wildflower seed mix I planted. Since the plot and a little bit of ground around the plot don't get mowed, there are some volunteer plants coming up. These have turned out to be a real magnet for pollinators. I've also noticed that some insects only feed on certain flowers. The bumblebees love the sweet basil flowers (which are almost gone). They don't seem much interested in the other flowers in the plot.

Anyway, I'm learning. I hope my images are getting better overall. I feel like they are. I remember trying my hand at macro back in the film days. What a disaster compared to what I am getting now.

 

[blackstar]

I don't consider it an intercept. This is the flash I've been using. The Amazon 2 has a small soft box. I picked up that when I first got my flash. Assuming it is the same size as mine, it works fine for macro work. Mine is 6 1/4" x 8 1/2". I prefer the homemade diffuser I put together. It is similar to the AK diffuser, although it is made of thin cardboard, duck tape and and old t shirt. It won't hold up long term, but it serves the purpose for now. There are several shoot through fabric diffusers on the market for around $10. I have one, and it works very well also. It is very convenient to use and store, and works about as well as the small soft box I have. Before I made my own diffuser, I would sometimes use the soft box in conjunction with the shoot through for extra diffusion, although I did lose some additional light power.

Most any of the diffusers will work fine to get started with. You will likely try several and settle on the one you like best. There are lots of articles and videos on the internet that go through the different types and show examples using them.

What about the AMZ1's round-type softbox or softcover? Now I noticed that both AMZs have a "green" button at the lower left, but B&H has that button "white". What's going on? Do they sell different products?

 

[blackstar]

OK, I'm now up for the Dummy of the Week award. I discovered this afternoon that somehow my flash was in an exposure compensation mode. I've not used the flash in TTL except for the one shoot when I first got it, until a couple days ago. I wasn't really paying attention to all the information on the screen of the flash, or bother to read the instruction manual on TTL. It was only for a -1/3 of a stop, but after resetting it to 0, things look better. Here is one of a handful I shot a few moments ago to test it out. This image was converted to a smaller JPG without any editing. It is still a tad on the dark side, as were the others, but it is pretty close to ideal IMO. I discovered if you put a TTL exposure compensation value in the flash, it stays. Even if you turn the flash off, it still remains when you fire it back up. Flash exposure compensation goes away when you turn the camera off, unless you safe the settings to one of the "user defined modes". Something to consider, if I feel that it needs some constant compensation. Judging by what I see from these handful, I think it is close enough.

View attachment 408166


Here is the same image, cropped and edited, with no Topaz help.

View attachment 408167

And another a little closer up. Boy these guys really love the thistles. Those are volunteer, and not part of the wildflower seed mix I planted. Since the plot and a little bit of ground around the plot don't get mowed, there are some volunteer plants coming up. These have turned out to be a real magnet for pollinators. I've also noticed that some insects only feed on certain flowers. The bumblebees love the sweet basil flowers (which are almost gone). They don't seem much interested in the other flowers in the plot.

View attachment 408168

Anyway, I'm learning. I hope my images are getting better overall. I feel like they are. I remember trying my hand at macro back in the film days. What a disaster compared to what I am getting now.

The last one is nice. I wonder if you change the aperture from f16 to f22, will it still work with the lighting situation and make a deeper DOF (maybe to cover the wings)?

 

[Clovishound]

I looked on B&H as well as Amazon, and couldn't find the AMZ1 you were asking about. I'm sure a round softbox would work very similarly to a square one.

Yes, I could use F22, and often do. It will increase DOF a little, in this case, probably not enough to get the wings in focus. The downsides are it requires more power from the flash, increasing recycle time and flashes per battery charge. The other issue is diffusion. I notice sharpness starts to fall off above F16. Most "gurus" recommend not shooting smaller than F11 for maximum sharpness. I'm sure that some lenses control it better than others. I need to set up a stable subject and shoot a series and compare them under magnification. I tried it this afternoon with a flower, but the wind interfered with the results. I could tell that F32 was definitely suffering from diffusion.

 

[Clovishound]

Update. After trying TTL mode for a while, I have gone back to full manual. The TTL works, but I am just more comfortable with making adjustments using manual. I probably can get less really off exposures using TTL, but I still get a lot of exposures that I want to adjust with TTL.

I believe it boils down to what I'm comfortable with, rather than this mode not working for me. It's easy enough to add or subtract exposure in TTL, but I can also very easily change exposure with a turn of the aperture dial on my camera as well as changing power setting on the flash.