Macro and Closeup--Autofocus Reconsidered

[bjanes]

The current opinion seems to be that autofocus is of limited utility in closeup and macro photography and may actually be a detriment, since the focus throw of most macro lenses is short. This short throw makes manual focus using the focus ring more difficult since a small movement of the ring causes a large change in focus. However, with the advent of live view and electronic control of focusing, the situation has changed. Autofocus in live view is more accurate than that achieved via the optical viewfinder, since it is achieved through contrast of the image on the sensor. With the optical viewfinder, focus is via phase and depends on accurate alignment of the reflex mirror and autofocus sensor, which is usaully at the bottom of the mirror box.

Electronic control of focus may be achieved in very small steps and the focus throw of the lens is no longer relevant. Live view focusing can be aided through the use of an external monitor. One can use HDMI, a USB connection, or Wi-Fi. Helicon remote implements focus stacking via the USB connection and can be used with a laptop or Android device. One merely chooses near focus by tapping the closest subject area on the screen and the far focus in the same manner. The software automatically takes the required number of shots for the stack. The Camranger also has a focus stacking option.

Various software controllers are available for Android, iOS devices and laptops. The tablet is more useful in the field than a laptop and may be used via USB or WiFi. Unfortunately, USB is not an option with iOS.

Personally, I would not consider buying a macro lens lacking autofocus. An ultrasonic motor rather than a mechanical autofocus linkage is highly desirable. For Nikon this means an AFS lens and USM for Canon.

Bill

[dwswager]

Both for me.  When doing closeup and macro, I generally opt to use the geared Kirk focusing rail which provides fairly fine movements compared to most focusing mechanisms and manual focus on the camera/lens.  If I don't have the focusing rail with me and depending on the situation, I normally use live view and AF as well as some potential manual focus tinkering.

I am old enough to remember when AF was too slow and imprecise to use for sports shooting.  Now, it is a different story.  So I am always rethinking and retesting my habits.

I will also add that I have picked up focus stacking as an option where the whole thing is done with AF set by Helicon Focus.  I then look at the stack and sometimes decide to pull 2-5 frames from the stack and discard the others to maintain some out of focus area.  The decision made for 'artistic' reasons.

[bjanes]

Both for me.  When doing closeup and macro, I generally opt to use the geared Kirk focusing rail which provides fairly fine movements compared to most focusing mechanisms and manual focus on the camera/lens.  If I don't have the focusing rail with me and depending on the situation, I normally use live view and AF as well as some potential manual focus tinkering.

I am old enough to remember when AF was too slow and imprecise to use for sports shooting.  Now, it is a different story.  So I am always rethinking and retesting my habits.

I will also add that I have picked up focus stacking as an option where the whole thing is done with AF set by Helicon Focus.  I then look at the stack and sometimes decide to pull 2-5 frames from the stack and discard the others to maintain some out of focus area.  The decision made for 'artistic' reasons.

I have the Kirk geared rail too and it is useful in some situations, but, in general, focusing by ring (the focus ring on the lens) gives better results with relatively low magnifications such as photographing a bouquet of flowers or a single flower. Rich Littlefield (author of Zerine Stacker) provides a good summary here.  He provides additional information here. Focusing by ring via an AF motor greatly extends the utility of focusing by ring.

Bill

[dwswager]

I have the Kirk geared rail too and it is useful in some situations, but, in general, focusing by ring (the focus ring on the lens) gives better results with relatively low magnifications such as photographing a bouquet of flowers or a single flower. Rich Littlefield (author of Zerine Stacker) provides a good summary here.  He provides additional information here. Focusing by ring via an AF motor greatly extends the utility of focusing by ring.

Bill

Interesting.  I probably use the rail from habit more than anything.  But you Rich's discussion centers on focusing individual slices of a stack.  There moving the camera has bigger implications typically than the small changes in perspective a very slight lens focus adjustment gives.  When I stack, I always use AF and let the system do the calculations on focus positions.

[Bart_van_der_Wolf]

I have the Kirk geared rail too and it is useful in some situations, but, in general, focusing by ring (the focus ring on the lens) gives better results with relatively low magnifications such as photographing a bouquet of flowers or a single flower. Rich Littlefield (author of Zerine Stacker) provides a good summary here.  He provides additional information here. Focusing by ring via an AF motor greatly extends the utility of focusing by ring.

The preference for lens focusing with focus-stacking is indeed related to magnification factor, and the related change in perspective by moving the position of the entrance pupil, rather than the image plane / sensor position. The focus rail approach can be particularly useful for extreme macro magnifications, where the Viewfinder image, or sometimes even the Live View screen, can become too dark to allow focusing and external flash is used for the actual exposures. Also with manual focus only lenses, a rail can come in handy. For automation, a 'Stackshot' kind of rail is ideal.

But in many cases, the AF/electronic focus enabled lenses offer lots of benefits, also for handheld shooting of close-ups. With flowers/branches swaying in the wind, or airborne insects, it's more than useful, especially if predictive focus or focus tracking can be used.

Cheers,
Bart

[pw-pix]

I've tended to get the framing and focussing close, then focus by moving myself and the camera back and forth very slightly when doing hand held macro work. You don't get the finest results as you would with a tripod, but it seems simpler than trying to hold the camera and manipulate the focus ring.

[ErikKaffehr]

Hi,

I use magnified live view for MF (Manual Focus) and it works reasonably well with most of mine lenses. I am aware of the Littlefield article, and he makes a good point for focus stacking using focusing on the lens.

Personally, I think that our mileage may vary, depending on circumstances.

Best regards
Erik

I have the Kirk geared rail too and it is useful in some situations, but, in general, focusing by ring (the focus ring on the lens) gives better results with relatively low magnifications such as photographing a bouquet of flowers or a single flower. Rich Littlefield (author of Zerine Stacker) provides a good summary here.  He provides additional information here. Focusing by ring via an AF motor greatly extends the utility of focusing by ring.

Bill