1

I am an Agronomic researcher assisting on a ML problem for identifying soy diseases. I would like to capture an image of a single range of soy (roughly 1' wide by 5' long) that is at least mostly in-focus (but will also be divided into smaller images for ease of clarity). Ideally experts will evaluate these fields, and their evaluation along with this image, will be passed along to train the algorithm.

I am using a Canon EOS 6D mark II for this project with an EF 24–105mm f/3.5–5.6 IS STM lens. I have tried taking some images in Av mode with a narrow aperture of up to f/22 which is the max it will let me do from an angle in front of the range. Only the top bit of the plants matters terribly much for this context. I have been using the autofocus option available, but centering the area in the middle of the top of the range. I have not tried editing shutter time yet, and I'm not really sure how to optimize.

Another question I have thought to ask:

Reducing the 1' width down to a 0-dimension for this figure, if the plants a roughly 2' tall, what angle must I be at to capture a clear image with what aperture and ISO options so that the tops (or the top of the green rectangle in this question) are mostly clearly visible?

Any and all advice is extremely welcome! I'm a relatively novice photographer, but the outcomes of this are decently important and photo quality is the number one parameter holding us up right now.

enter image description here

Edit

I was asked to post some of the photos we'd being using:

So here is with autofocus: (link to full size)

enter image description here

With narrowest aperture, f/22: (link to full size)

enter image description here

Ideally we can get this clear enough that we can train both a ML algorithm on this AND have professionals rate it from photos alone.

9
  • Please post some of the photos, along with a description of what you'd like to improve about them. Also be aware that f/22 is the narrowest aperture that your lens will do, not the widest. – Philip Kendall Sep 2 '20 at 19:07
  • "with a wide aperture of up to f/22 which is the max" FYI F22 is a narrow aperture, The higher the number the smaller the aperture. "which is the max it will let me do from an angle in front of the range" I do not understand how aperture is related to what angle you are shooting. ? – Alaska Man Sep 2 '20 at 19:07
  • "Reducing the 1' width down to a 0-dimension for this figure, if the plants a roughly 2' tall, what angle must I be at to capture a clear image with what aperture and ISO options so that the tops (or the top of the green rectangle in this question) are mostly clearly visible?" - The goal is to show a cross section of the tops of the plants to evaluate the health of the plants. ? Is The purpose of the angle is to show as much of the tops of the plants as possible (fill the frame)? – Alaska Man Sep 2 '20 at 19:11
  • I'd lay out a rectangle of paper or carpet (or actual soybeans) and take some test images at various apertures. Take a look at them and see what works. The greater your viewpoint angle the less you'll need to stop down. – BobT Sep 2 '20 at 22:30
  • @AlaskaMan Yes, that is exactly the point to fill the frame with the x-section of the plants! – Drew Sep 3 '20 at 15:48
2

If I understand correctly, it sounds like what you want is a Tilt/Shift Lens.

This will allow you to adjust the focal plane to be more in line with your shot.

Some quick examples from the web:

Marc Muench on Using a Tilt-Shift Lens

Marc Muench on Using a Tilt-Shift Lens

Using Lens Tilt for Landscape Photography

Using Lens Tilt for Landscape Photography

Be aware that these lenses are not Cheap, as in around $2000 for a Canon Tilt/shift.

1
  • This is pretty good advice! I didn't know these existed! I'll definitely pass this along and see if it's in the budget. – Drew Sep 3 '20 at 15:32

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.