Sony A7 V Questions about focus stacking with flash

[CCRphoto]

I'm an underwater photographer who is considering upgrading equipment to an A7 V, and being a glutton for punishment and pushing the boundaries I am wanting to try focus stacking underwater - wish me luck!

The questions I have relate to the frame rate when focus stacking / focus bracketing.

When selecting the Shooting Interval it gives you the option of
- Shortest
- 1 Second
- 2 Second
- 3 Second etc.

What actually determines the FPS when you choose "Shortest"?

 

[iamdlewis]

What actually determines the FPS when you choose "Shortest"?

The shutter release reset. There are two factors involved in this, the first is your shutter release setting and the second is the maximum performance of the shutter.

Your Shutter Release can be set to Focus Priority, Balanced or Release. The Focus will only trigger the next shot when the AF thinks it has focus on something, the Release will trigger with the least amount of time is possible regardless of focus and Balanced is somewhere between those.

The maximum release speed will depend on if you are shooting mechanical or electronic. So in mechanical the A7V can do 10fps, so basically the camera can take an image every 1/10 of a second, so the shortest time between shots will be about 1/10th a second. In electronic you can do 30fps so the shortest time between will be about 1/30th.

Good luck with this. It is difficult enough to do without the constant movement in water.

 

[CCRphoto]

The shutter release reset. There are two factors involved in this, the first is your shutter release setting and the second is the maximum performance of the shutter.

Your Shutter Release can be set to Focus Priority, Balanced or Release. The Focus will only trigger the next shot when the AF thinks it has focus on something, the Release will trigger with the least amount of time is possible regardless of focus and Balanced is somewhere between those.

The maximum release speed will depend on if you are shooting mechanical or electronic. So in mechanical the A7V can do 10fps, so basically the camera can take an image every 1/10 of a second, so the shortest time between shots will be about 1/10th a second. In electronic you can do 30fps so the shortest time between will be about 1/30th.

Good luck with this. It is difficult enough to do without the constant movement in water.

It is certainly going to be interesting - a few people on an underwater photography forum reckon it will be impossible underwater but I'm up for the challenge!

Many thanks for that info. With the underwater strobes (flashes) that I use, at a power setting for macro they will be able to keep up at about 6 fps, but I am unsure about 10 fps. I don't want to use the 1 second option in the menu as a long focus stack will take several minutes. Assuming that using mechanical shutter is OK and selectable when using the Focus Bracketing setting, then selecting Focus Priority might hopefully be enough to slow things down to about 6 fps.

The underwater strobes that I use are activated by a flash trigger that mounts on the hotshoe - when it receives a signal from the camera/shutter to fire the trigger activates two small LED's that line up with small windows fitted to the housing shell - on the outside of these windows there are fibre optic cables that run to the strobes and when the strobes receive a light signal they fire. This is the preferred method for firign strobes these days because as you can imagine salt water and electrical cables/contacts aren't a great solution.

 

[iamdlewis]

It is certainly going to be interesting - a few people on an underwater photography forum reckon it will be impossible underwater but I'm up for the challenge!

At least the worst that happens is you delete some images. So much cheaper than film. I would take a greater depth of field image first and then switch to the stacking settings as I feel like the others do.

When I have done macro with flashes I know I can't set my flashes to 1/2 or 1 power when using the focus stacking or 10FPS. Unless I am using the 50mm macro there is no chance of slowing things down enough, these cameras and lens just focus too fast. Man that sounds silly to write.

as you can imagine salt water and electrical cables/contacts aren't a great solution.

I've had a couple phones that would agree with that.

 

[CCRphoto]

At least the worst that happens is you delete some images. So much cheaper than film. I would take a greater depth of field image first and then switch to the stacking settings as I feel like the others do.

When I have done macro with flashes I know I can't set my flashes to 1/2 or 1 power when using the focus stacking or 10FPS. Unless I am using the 50mm macro there is no chance of slowing things down enough, these cameras and lens just focus too fast. Man that sounds silly to write.


I've had a couple phones that would agree with that.

I think that it is doable provided I am using a tripod and choose suitable subjects - anchored invertebrates instead of fish etc. The Retra Maxi strobes have a guide number of 46 and very fast recycle time. If I can make focus bracketing work then it will enable the entire colony to be in focus in an image like this which would be much better than looking at an image like the one shown.