Focusing issues with Sony 90mm 2.98 macro when shooting teeth (im a dentist)

[DRVGV]

I am a dentist that loves photography and documenting my cases but im stuck with shooting manual mode with my sony A1 and 90mm lens. When I use autofocus the lens goes crazy tryign to find a focus even when i shoot from the rigth length setting on the lens. It's something I miss that i used to get with my old canon 5d mark iii and 100mm lens. When i used the canon, I used to shoot autofocus and regarldess where i would point it would focus right away at the teeth. Part of the problem with the sony is that in low light (inside the mouth) its hard for the camera to find the focus (the canon dslr didnt ahve this problem). Does anyone have any recommendations to help me? Thank you and much appreciated. 

 

 

[CarolineJensen]

This is so interesting! Does it have an issue if you use spot focus and choose the tooth you want to focus on? 

[CarolineJensen]

Also, how much light do you have illuminating the mouth? Is the overhead light on --the one they turn on for cleaning, or is it more of a sitting up situation? 

[Drew_Geraci]

The amount of light might indicate why the focus is going crazy but to put it bluntly the 90mm Macro is one of Sony's first lenses and doesn't have the same AF technology you would find in their newer lenses. I think we're all waiting on pins and needles for a new Macro to launch (and hopefully soon!). For the time being, I would recommend using more light (so it can see the contrast needed to find focus) or use manual focus and a micro-adjuster ball head so you can move mm back and forth for the perfect focus. 

[CarolineJensen]

The amount of light might indicate why the focus is going crazy but to put it bluntly the 90mm Macro is one of Sony's first lenses and doesn't have the same AF technology you would find in their newer lenses. I think we're all waiting on pins and needles for a new Macro to launch (and hopefully soon!). For the time being, I would recommend using more light (so it can see the contrast needed to find focus) or use manual focus and a micro-adjuster ball head so you can move mm back and forth for the perfect focus. 

I second an updated macro!

[pm-r]

Hey Doc, I bet part of the issue is that you are closing the lens down to get enough depth of field when trying to AF.  Try using "tracking:flex S" AF area and that should help.  If you are using a flash, definitely switch to AF-S and the AF should settle down and work fine.  If you are stopped down to f/11 or f/16, the camera can't see to focus, especially inside a mouth.  Let me know here what your settings are so I can help you further.  pm-r 🙂

[GaryHart]

First, I agree with Drew's comments. What Focus Area are you using? As a landscape shooter, I always use Flexible Spot (Small, Medium, Large), and have found that the smaller the spot, the harder time my cameras have finding focus. But regardless of what you use, I'd definitely play with different Focus Area settings.

[davidmclain]

Hi Doc, I've used this lens a ton over the last several years to shoot food. The lower the light and the closer you are to your subject, the less responsive the AF is. In your situation, I would recommend getting as much light on the teeth as possible, and shooting with manual focus. Rather than fine-tuning the focus with the lens ring, try fine-tuning it by moving the camera a little closer or further away from your subject. You'll get good as this quick. Give it a try.