105 mm focus stacking

[bs0604]

I am thinking of getting the 105 mm lens for macro work. But in reading the reviews at Adorama I came across this statement in one of the reviews: the lens suffers from "focus breathing" and image changes sizes with change in focus making it impractical for focus stacking.
Any thoughts on this limitation of the lens if I was hoping to do focus stacking?

 

[greybeard]

It does breath quite a bit but focus stacking in PS/CS5 seems to take it into account.

 

[cgipson1]

I focus stack with mine all the time. Depends on how you focus stack...

There is a handheld (braced against a post) example using the actual focus ring for the stack - 31 images) (this is what would show the "focus breathing" the worst... I consider this acceptable, do you? The flower was about 3/4" in diameter, shot at F22 with my Nikon 105 macro



[Camera]
Exposure time: 1/250"
F number: F22
Exposure program: Manual
ISO speed rating: 200/24°
??? (8830): 2
Exif version: Version 2.3
Date and time of original data generation: 2012-08-11 07:57:46
Date and time of digital data generation: 2012-08-11 07:57:46
Meaning of each component: YCbCr
Image compression mode: 4 bpp
Exposure bias: ±0 EV
Maximum lens aperture: 4.2 Av (F4.3)
Metering mode: Spot
Light source: Cloudy weather
Flash: Flash fired, compulsory flash mode, return light not detected
Lens focal length: 105 mm
Manufacturer notes: 0x00000474
User comment:
DateTime subseconds: 0.2"
DateTimeOriginal subseconds: 0.2"
DateTimeDigitized subseconds: 0.2"
Supported Flashpix version: Version 1.0
Color space: Uncalibrated
Image width: 7360 px
Image height: 4912 px
Interoperability IFD Pointer: 0x00009C70
Sensing method: One-chip color area sensor
File source: Digital Camera
Scene type: A directly photographed image
CFA pattern: [Red, Green], [Green, Blue]
Custom image processing: Normal process
Exposure mode: Manual exposure
White balance: Manual
Digital zoom ratio: 1x
Focal length in 35 mm film: 105 mm
Scene capture type: Standard
Gain control: None
Contrast: Normal
Saturation: Normal
Sharpness: Hard
Subject distance range: Unknown
Gamma: 2.2

 

[bs0604]

cgispon1:
your flower is beautiful, more than acceptable.
when you say you used 31 images. Do you just manually move the focus ring a mm or two between each of the 31 shots?
Did you use f22 to increase depth of field for each shot, as opposed to using a lower f stop?

 

[tirediron]

Bear in mind that the way to acheive optimum results in focus stacking is with the use of a focusing or macro rail. This allows you to change your point of focus very precisely and in even increments WITHOUT touching the focusing ring on the lens, negating any impact of the 'focus breathing'.

 

[Mully]

Very nice Charlie... explain this for those like me who don't quite get the technique

 

[cgipson1]

Bear in mind that the way to acheive optimum results in focus stacking is with the use of a focusing or macro rail. This allows you to change your point of focus very precisely and in even increments WITHOUT touching the focusing ring on the lens, negating any impact of the 'focus breathing'.

Agreed! This is the best way to focus stack.. but I didn't have a rail handy that day! lol! A rail totally removes any chance of "Focus Breathing" being an issue!

 

[cgipson1]

cgispon1:
your flower is beautiful, more than acceptable.
when you say you used 31 images. Do you just manually move the focus ring a mm or two between each of the 31 shots?
Did you use f22 to increase depth of field for each shot, as opposed to using a lower f stop?

Yes.... a fraction for each image. Normally I focus stack (with a rail) at F8 to F11... to totally negate any diffraction softness. But since I was doing this handheld... I wanted as much DOF as I could get for a safety margin.

Thank you, glad you like it!

 

[cgipson1]

Very nice Charlie... explain this for those like me who don't quite get the technique

I was in a sitting position with a upright post and the flower between my legs. I basically rested my hand, and shoulder against the post with elbows on my knees... trying for as much stability as possible. I then shot the flower after focusing on the very tip of it, closest to me. I moved focus out just a tiny fraction.. the smallest actual movement I could make on the lens. Kept shooting and moving focus... until I got to the far edge of the flower. Then I stacked the images with Zerene Stacker... and cleaned up the background a little in PS.

I was using diffused flash (6"x8" softbox)... on camera for light (manual mode).

Glad you like it Mully! It is fun to do this.. but difficult by hand obviously. Works very well on a tripod though!