How can I get accurate focus for top-down product shots in low light using flash and modeling lights?
Asked 3/4/2022
69 views
2 answers
0
I’m photographing textiles from above with two flashes. Their modeling lights aren’t bright enough for reliable autofocus, and the fabric often has little texture or no strong edges. The camera is about 70 cm above the subject, and the textile surface is only about 0.5 cm above the table. Live view over tethering is noisy and not detailed enough to judge focus precisely. What’s the best way to focus accurately before firing the flashes? Can I use a temporary focus target such as printed text, and will a 0.5 cm height difference matter?
Originally by Photography Stack Exchange contributor. Source · Licensed CC BY-SA 4.0
Photography Stack Exchange contributor
4y ago
2 Answers
3
The simple solution is to install a bright third lamp with push-button on/off switch. You turn this lamp on to elevate the ambient light, now you can compose and focus with ease. When ready for the shot, turn off this lamp and take the shot.
Additionally, substituting a printed target or removable focus aid object will work.
Will the ½ centimeter difference between target and object impair focus? Not likely, especially if you are using a f-stop below the middle range like f/11 or better f/16. These small apertures provide sufficient depth-of-field allowing tiny focus errors to become moot.
Originally by user44949. Source · Licensed CC BY-SA 4.0
user44949
4y ago
0
Generated from our catalog & community — verify before relying on it.
Yes—this is a common product-photography problem, and the usual fix is to separate focusing from shooting.
Use a tripod, add a bright temporary light (lamp or flashlight), and focus before taking the shot. Once focus is set, switch the lens/camera to manual focus so it won’t change, turn off the extra light, and then fire the flashes with a trigger or remote.
A temporary focus target is also a good idea. Place something with clear contrast or edges where the textile will be, focus on that, then remove it before shooting. If possible, use a stand-in object at the same height as the fabric surface.
Will 0.5 cm matter? Usually not much, especially if you’re shooting at a smaller aperture such as around f/11 or f/16, where depth of field helps cover tiny focus errors. But for the most accurate result, focus at the actual subject distance whenever possible.
If you only need to photograph many items from the same setup, focus carefully once using magnified live view, lock focus manually, and keep the camera position fixed.
Recommended products
UniqueBot
AI4y ago
Your Answer
Related Questions
How should I set up an overhead camera to photograph large flat manuscripts clearly?
Should I use clear or opaque acrylic for a backlit product photography table?
Which lens for stronger background blur and quiet autofocus on a Canon M200 for streaming?
Why are my night landscape photos blurry even on a tripod?
What focus-assist light is least likely to disturb spiders and insects during night macro photography?