Flash for stacking?

[Oldbear67]

Beginner here.

I am trying to image small specimens (1 to 2 mm) with a DSLR and a Nikon objective. I am concerned with camera shutter vibration (CanonT5) and considering going to flash.

Is there an inexpensive flash system that will cycle fast (2 to 5 sec), and can image 100 frames without burning through wheelbarrows of AA batteries?

[Scarodactyl]

If you shoot in live view the T5 has efcs. There shouldn't be any issue with shutter shake.

[colohank]

No matter which flash units you use, remember the law of inverse squares and strive to position them as close as you can to the subject without introducing glare or reflections. When flash-to-subject distance is reduced, so is the duration of flash pulses needed for proper exposure and the time needed to re-form the flash capacitor between shots. At 1/128 power, my fully charged Godox MF-12 units can easily produce two hundred or more flashes at less than one second intervals. The MF-12s have a built-in lithium-ion batteries. If your flash units rely instead on AA batteries for power, then by all means switch to rechargeable NiMH Eneloop Pro batteries or the equivalent. I understand that the Eneloops can be recharged hundreds of times, so cost-savings compared with disposable single-use batteries are considerable.

[MarkSturtevant]

Is there a reason why continuous lighting through an AC power source cannot be used?

[Oldbear67]

Is there a relatively inexpensive flash that will operate with 110 V?

[colohank]

I often use continuous LED lighting to illuminate macro subjects, but without extra precautions, there's always the chance that vibration during the exposure will soften images. Thus, I shoot only in mirror-up mode (Nikon) when shooting macro. In that mode, a first actuation of the shutter button raises the mirror and, after a momentary delay to allow mirror vibrations to damp, a second actuation trips the shutter (I don't press the shutter release manually but program a StackShot to do that electronically). A remote release would work, as well. I'm not familiar with Canon DSLRs but assume that they offer a similar function. I compose my frame in Live View and could also shoot in that manner, but the continuous display would exhaust the camera's battery more quickly, so I shut if off before starting my stack.

At low power levels, the pulse of light from a flash is so brief that it does a better job of freezing the subject than a continuous light. On the other hand, it's a lot easier to gauge exposure levels using a continuous light source. As always, every option and decision involves trade-offs.

[rjlittlefield]

If you shoot in live view the T5 has efcs. There shouldn't be any issue with shutter shake.

Scarodactyl makes an important point, which I'm worried has gotten lost in the chatter.

When Canon cameras are in live view mode, with the shutter already open, taking a picture can begin with the sensor being cleared electronicically.

This is called EFSC -- Electronic First Shutter Curtain -- and there is no mechanical movement of the mirror or shutter at this time.

The exposure is ended with the shutter closing mechanically, but in most cases that movement is only a small fraction of shutter open time so it does not affect image sharpness.

There are a few tricky aspects that sometimes cause trouble:

• The camera must be showing the live view image on its own display back, or remote controls such as shutter activation may be ignored.
• Resetting of the shutter may also cause the mirror to drop and rise again, which can produce lots of vibration after the exposure.
• You must not attempt to use flash in EFSC mode. Either the camera will fail to trigger the flash at all, or the camera will fall back to normal mode and cycle the mirror down/up just before the exposure, which causes a huge amount of vibration.
• Shooting in live view mode for an extended period causes the sensor to get hot, which increases pixel noise and makes warm pixels more troublesome.
• Shooting in live view mode runs through batteries faster, so it's best to an AC adapter to power the camera.

Clearly there are tradeoffs involved in using EFSC, but if the downsides can be tolerated then the upside of no vibration to start the exposure can be wonderful!

Oddly, Canon manuals are almost entirely silent (pun intended) regarding EFSC. The feature has been around for a long time and is well known in some circles, but Canon hardly ever mentions it. For some early documentation, see https://krebsmicro.com/Canon_EFSC/ .

--Rik

[Marcepstein]

Rik,
Im confused about the 1st curtain sync and flash that you mentioned - Im probably misreading something:

You must not attempt to use flash in EFSC mode. Either the camera will fail to trigger the flash at all, or the camera will fall back to normal mode and cycle the mirror down/up just before the exposure, which causes a huge amount of vibration.

On my EOS 1D Mark 1V (older camera), I have it set to 1st curtain sync and the flash fires just after the exposure starts in Live view or, in a special function Ive set wherein the mirror does not close but remains up for continuous shots like stacking. So, on the first exposure, the mirror locks up, a few moments later the curtain opens, flash fires, exposure timed, curtain closes, but mirror remains up, ready for the next exposure and does not close until the live view button is activated. During this latter setting, live view is not available. The camera information settings are displayed on the rear screen but not a live view of the subject like you’d normally see in live view. But I do compose the image first with live view and flash to test if my lighting settings are sufficient. Then I use this custom function to continue with the shots.

PS: Happy New Year

[rjlittlefield]

Marc, I suggest to remove the lens, set say 1 second exposure time, and look into the front of your camera while it is operating in the modes that you describe. If you start in live view mode, then I expect what you'll see is that just before the flash fires, the shutter closes and immediately opens again. That is the camera operating in normal mode, with mechanical first shutter curtain. Then, unplug the flash from the camera and repeat the experiment. Successful use of EFSC will result in no movement of the mechanical shutter at start of exposure.

One caveat... With some Canon cameras, EFSC mode is automatic whenever the camera is in live view mode and flash is not attached. With other Canon cameras, you have to also make some explicit setting like "silent mode 2" or something like that. But I have never had hands on such a camera and I'm not sure exactly what the required setting might be on an 1D Mk IV.

--Rik

[Marcepstein]

Ok, this will be interesting.

[Marcepstein]

Ok, I ran the experiment and it was very interesting. The first time it went so fast that I couldnt tell what was happening so I videoed it in slow-mo with my Iphone. I noticed the shutter activation and flash behaved differently when the flash was in manual or auto mode so I did 5 different test. I used a canon macro twin lite MT24ex. Odd that the camera and flash manuals do not really address flash photography in live view very much. In the 1DMIV manual, it "indicates" that the flash works in live view but is non-descriptive. It just says that the external speedlite will not emit an AF assist beam during live view and a little about flash exposure compensation in live view - how to set the auto lighting optimizer, and that the FE lock and modeling flash doesnt work in live view. I googled live view and MT24ex flash and there was not much there. The 1DMIV does have a custom function for "silent mode" where after the first exposure, the mirror remains up for continued exposures until the photographer releases the program. Live view is not available during this setting so that is why I was using live view (with flash) to set composition and flash exposure prior to using it. The 1DMIV manual does not mention “electronic” first shutter curtain only “flash sync” where 1st curtain is the default setting for the camera. I’ll be glad to share the videos as there’s probably more to this than my untrained and inexperienced eyes can interpret.

A question that comes to mind with electronic first shutter curtain not employing flash - would continuous lighting like LED be recommended in lieu?
Here are the test.

Results: this is what I see, even with slow-mo it happens pretty fast.
1. Live view flash in manual mode: live view activated mirror locks up, sensor exposed, curtain activated, big flash, sensor exposed, curtain activated/de-activates, then back to live view with sensor exposed.
2. live view flash in auto mode: live view activated mirror locks up, curtain activated, mirror comes down, flash fires, mirror back up with curtain showing, second bigger flash fires, mirror locks up, sensor showing, curtain activates/de-activates and then back to live view with sensor showing.
3. silent mode auto flash - 3 exposures: shutter released, mirror locks up with curtain showing, flash fires (mirror stays up) and the scenario (with mirror up) repeats for 2 more exposures.
4. silent mode manual flash - 3 exposures: shutter released, mirror locks up with curtain showing, flash fires, sensor showing, mirror stays up and the scenario (with mirror up) repeats for 2 more exposures.
5. live view no flash: live view activated mirror locks up, curtain activated, de-activates, sensor exposed, curtain activates/de-activates, sensor showing in live view.

I think I recorded this correctly?

[rjlittlefield]

Marc, all that makes sense. Slo-mo video recording is a nice touch. That made me check my own new Pixel 6a. 240 fps -- nice!

About your camera... I noted in searching the web that https://www.mhohner.de/newsitem2/efcs has a comment from Pau that "EFSC is a feature implemented in almost all Canon EOS dSLR cameras with Live View (with the exception of some 1D series models)". That comment, plus your observation #5 for "live view no flash", made me suspect that your 1D does not support EFSC. I searched the forum here using some special admin magic and found a post by Charles Krebs from 2010 that says

I don't believe that any of the Canon 1D series bodies have the capability of EFSC.

All other posts are consistent with that, except that some later posts indicate that 1DX does have EFSC.

Summary: bad news, it looks like your camera does not have EFSC.

--Rik

[Marcepstein]

Yeah, Im due for a camera and software upgrade. Klevin mentioned a Canon M6ii as a nice option in an earlier post. There are a lot of decient EOS bodies out there that would work for macro and still be compatible with my lenses. In the mean time, we'll see if the 1D can produce a decient image. Tks, that was an interesting experiment.

[Oldbear67]

Some of the astronomers are going to mirrorless cameras. I suspect that that would be my next purchase for astro and ento photography; assuming I don't go for something more esoteric.

[Macro_Cosmos]

Two things to note from my personal experience:
- Flash can cause fine displacement, so shield the subject. You should be diffusing it anyway. Some may disagree but I have seen it happen. Put the flash at full power, close eyes, and press it against your skin, fire it and you will sense a tickle.
- Output variation, this exists even among expensive units, though not so much on good quality studio lights such as AlienBees. Many programs can equalise the variation, Lightroom has it.