Tips for using Sony 90 mm Macro?

[JFairleigh]

Hey everyone, I've only taken my macro lens out on a couple of dives, and I'm having trouble dialing in the settings. The focus hunts underwater, and I'm finding it difficult to convince it to lock onto squishy small creatures rather than the rocks they're sitting on.

Lens: 0.5m-0.28m
Optical steady shot=off

Camera: Single-shot AF
Focus Area Spot: S
Steady shot: Off
Subject Recog in AF: On
Recognition Target: Animal/Bird
Metering Mode: Spot (standard)
DRO: Auto

I was shooting baby red octos which were hunting in and around cobbles roughly 4-6" in size. Aperture ranged from f/14-f/22. I'm using a focus light, an external viewfinder, and a pair of Sea & Sea YS-D3 MKII. I have my camera set up for back-button focus. Even when the shot looked clear through my viewfinder, I could see I hadn't nailed the focus in my image playback.

Out of 34 shots, only 10 were in focus and I think those were accidental. In several, the camera focused on the barnacles right next to the octopuses. The subjects weren't moving fast, and I was pretty much stationary. What am I doing wrong?

 

[PatW]

I shoot a Nikon Z8 often with a Z 105 f 2.8 macro.

I would advise shooting in auto focus continuous rather than single shot AF. I shoot single shot AFC. I shoot virtually entirely suspended in the water column. That means that I am not stable like one would get with a tripod. So continuous is good with a flash and shutter speed that is rather high to freeze action. Even then it is easy to be out of focus because of the delay between my moving from say surge, the camera focusing and my delay from actually squeezing off the shot. But I do surprisingly well considering the difficulties.

Since you are shooting macro, you are probably pretty close to your subject. If you shoot wide open on F stop, you will have a very narrow depth of field. That is OK if 1) you nail the focus and 2) you are OK with the probability that most of the photo will be out of focus. So you will need to have a higher f stop often. Depending on distance this can be F5.6 all the way up to F24. At higher F stops there will be loss of detail from diffraction. The only way to circumvent diffraction is to shoot at lower F stops. It is not a matter of lens quality. It is a matter of physics.

And of course, you should use strobes and preferably 2 of them.

So what are you doing wrong?

I would suggest spot focus and I shoot manual. I don’t use subject recognition. I think subject detection Animal is set up for cats, dogs and maybe large mammals. I am not confident in it working on alien looking stuff like arthropods (crabs, lobsters etc). It might do better on octopus and fish.

But I find that my Lightroom software is iffy on subject detection in masking for fish, birds and you can forget crabs and lobsters as well as divers, So I am not keen on the camera identifying divers. I have found that a spot focus or small area focus can work pretty well (you might use animal in small area focus and see how it goes). I find in Lightroom if I select object for masking it often does far better. AI is not all that it is cracked up to be.

And yes, the camera can LOVE, LOVE, LOVE to focus on gravel. I find in shooting pearly jaw fish that my camera will almost always avoid the soft contours of the fish and go for the background if I give it half a chance. One trick is to focus on the bottom right next to your subject and then shift to the subject and refocus. It usually works pretty well. Not always.

 

[JFairleigh]

Thanks Pat! It looks like your lens has 2 focus settings; Full or 0.5m-0.29m. Which do you use?

 

[PatW]

Generally I use full because if I run into a larger subject, I may need to back off some.

Don’t be too hard on yourself generally 1 or 2 nice shots per dive is doing well.

 

[hilljo88]

I shoot the Sony 90 macro lens. It is very sharp but does tend to hunt limiting the focus range is a good idea, especially if you are shooting macro subjects. F12 f16 helps to deepen DOF. Rocking back and forth to bracket several shots helps to get at least one in focus. I find having a bright focus light also improves the lens focus. Don’t get discouraged, keep shooting

 

[JFairleigh]

I shoot the Sony 90 macro lens. It is very sharp but does tend to hunt limiting the focus range is a good idea, especially if you are shooting macro subjects. F12 f16 helps to deepen DOF. Rocking back and forth to bracket several shots helps to get at least one in focus. I find having a bright focus light also improves the lens focus. Don’t get discouraged, keep shooting

Thank you so much! Which lens setting do you use? Also, do you use optical steady shot on the lens? The body? Both? Neither?

 

[PatW]

I am lucky. The Nikon z 105 focuses fast . But it works better on some things than others. It locks onto butterfly fish. It does not like pearly jaw fish. I would bet that any lens would have problems with an octopus. But 60 mm micro did well with them. It might have been the depth of field.

I use VR on the camera and lens just fine. So that should be OK.

Remember autofocus works best on things with nice edges which barnacles have and nice smooth octopus don’t.

Now I find that on most subjects the Z8 focuses pretty well in low light. But a focus light will only help.

 

[Barmaglot]

I've used this lens for years on an a6300 - it sounds like you have a considerably newer camera, which more advanced autofocus. In my experience, the most important thing about using this lens is staying still. I keep settings simple - AF-S, or AF-C, center focus, ISO 100, 1/160s, f/16 or thereabouts (f/22 for supermacro shots with diopter). I find the focus range limiter to be highly annoying and not particularly useful in terms of improving focus speed, so I never use it. The critical thing is, again, to keep the camera absolutely still while it focuses - if there is any movement at all, it will hunt forever. If the subject is, for example, sitting on a branch that's swaying in a surge, then I don't even bother trying - better to look for something that sits on a nice static rock or coral. Likewise for blackwater - I use a Canon 60mm on a Metabones adapter for that.

Earlier this year I upgraded to an a6700, but right afterwards I've had to take a break from diving, so I only had a change to take it on a couple dives thus far. On the newer body, it seems a lot better at tracking moving subjects - with AF-C engaged, it seems to track even fairly fast-moving fish around the frame with little issue, something that the a6300 was awful at (at least with this lens). Subject recognition doesn't seem to be of much use underwater. In the scenario that you describe, it sounds like setting focus to just the center of the frame and making sure the subject is in the crosshairs prior to grabbing focus should eliminate most of your issues.

 

[JFairleigh]

I've used this lens for years on an a6300 - it sounds like you have a considerably newer camera, which more advanced autofocus. In my experience, the most important thing about using this lens is staying still. I keep settings simple - AF-S, or AF-C, center focus, ISO 100, 1/160s, f/16 or thereabouts (f/22 for supermacro shots with diopter). I find the focus range limiter to be highly annoying and not particularly useful in terms of improving focus speed, so I never use it. The critical thing is, again, to keep the camera absolutely still while it focuses - if there is any movement at all, it will hunt forever. If the subject is, for example, sitting on a branch that's swaying in a surge, then I don't even bother trying - better to look for something that sits on a nice static rock or coral. Likewise for blackwater - I use a Canon 60mm on a Metabones adapter for that.

Earlier this year I upgraded to an a6700, but right afterwards I've had to take a break from diving, so I only had a change to take it on a couple dives thus far. On the newer body, it seems a lot better at tracking moving subjects - with AF-C engaged, it seems to track even fairly fast-moving fish around the frame with little issue, something that the a6300 was awful at (at least with this lens). Subject recognition doesn't seem to be of much use underwater. In the scenario that you describe, it sounds like setting focus to just the center of the frame and making sure the subject is in the crosshairs prior to grabbing focus should eliminate most of your issues.

This was helpful, thank you! I'm going out again this weekend. With luck (and no floods) I'll get in at least two dives. I've changed my focus settings and am excited to test them.

 

[staggsSevin]

I've used the 90mm on a7ii, a6400, a6600 and now a A7VR....it became a better lens over the years as I upgrade cameras (a7ii i never took underwater but used the lens topside). The a6600 it became a game change up top or down below as it focused very quick.

I've only used it on the a7rv topside, my next trip is in April in the maldives so I probably won't bother packing it.

I run very similar settings as Barmaglot mention on my a6600 (which has been my primary u/w rig until this month...just purchased a7rv setup, and i utilize a nice focus light as well.