CHG_CANON Loc: the Windy City

Depth of Field is both a technical and artistic decision. Your lens may limit how 'wide' you can set the aperture for that lens. Wide aperture lenses, aka 'fast' lenses, can let in lots of light, just like the pupil of your eyes in a dark setting. A wide aperture will also tend to provide more of a blurred background. So, do you need a wide aperture for low-light or for the art?

Personally, I tend to prefer an image where I can determine / understand the subject, as demonstrated in these lilac images. I shot over three days in May 2020, and some of the first day's results were so blown-out, I wouldn't know that I was looking at lilac blossoms, even if you told me. Trying to practice what I preach, I reviewed the results, determined corrective actions, and went out again and shot with these updated parameters.

Images presented range from f/3.5 (the max for this prime macro lens) and f/14. I didn't keep notes, written nor mental, when capturing these images. I thought of this post later as I reviewed the results. Two of the images are 'moderate' apertures of f/5.6 and f/6.3, with moderately unfocused backgrounds. Hopefully, the images demonstrate the ideas presented in the text and will be useful to your photography.

Lilacs in bloom by Paul Sager, on Flickr


Depth of field is the distance between the closest and farthest objects in a photo that appears "acceptably sharp". Even though your camera can only focus sharply at one point, the transition from sharpest focus to unsharp is gradual, where the term ‘acceptably sharp’ is a loose one. If you want to get deeper into the science, just google something called the "Circle of Confusion". Have fun.

Canon EOS 5DIII and EF 180mm f/3.5L macro. The images were captured in RAW and processed in Adobe Lightroom 6 with Topaz DeNoise 6.
Chicago, IL
May 2020

Lilacs in bloom


Depth of Field (DoF) is impacted by (a) the lens aperture used for the image, (b) the distance between the camera and the subject, and (c) the focal length of the lens. The lens aperture is probably the first thing most photographers think about when they want to adjust the depth of field. Large apertures, which correlate to small f-stop numbers, tend to produce a very shallow depth of field. On the other hand, small apertures, or large f-stop numbers, tend to produce images with a large depth of field.

Lilacs in bloom


The shorter the distance of the camera to the subject, the smaller the depth of field. The images presented in this topic use a variety of distances and apertures, all from the same 180mm focal length. These images range from probably 12-inches to over 2-feet, all relatively 'close' to the blossoms. If you've ever tried close-up images of flowers or insects, you've probably noted how hard it is to get the entire subject in focus, even with a small aperture.

Although we tend to think of 'longer' focal length macro lenses as providing a greater working distance between the camera and lens, that longer focal length can also be used to isolate the subject from the background via a narrow DoF. A shorter focal length lens will tend to have a greater depth of field to the same subject as compared to a longer lens. This is why it's difficult to create a dreamy / creamy background with a wide-angle lens.

These lilac images employ all three variables of controlling the DoF: wide (or narrow) apertures, a relatively longer focal-length macro lens, and the camera relatively close to the subject via a tripod. Although not mentioned earlier, the sensor size also impacts the DoF, although this idea is caused by the cropping of the image that serves to truncate the circle of confusion. That is, the image has the same DoF as a full-frame, but you can't see the entire image due to the cropping.

Lilacs in bloom


These images are sized to fill your wide-screen display. Try using <F11> to maximize your browser window for the full effect. If the images overshoot your display, such as a laptop, just click on the image or the URL link and they'll resize to your screen from the host Flickr site. You can click a bit further into the image details on the Flickr page, if desired. EXIF data is available from the host Flickr pages as well. On the Flickr site, use your <L>key for Large and the <F11> for the full-screen.

If the images are not filling your widescreen display due to recent UHH changes, follow this link and update your UHH profile: https://www.uglyhedgehog.com/t-572300-1.html

Dr J Loc: NE Florida

Well done review and images to illustrate. Thank you!

Country Boy Loc: Beckley, WV

Paul, this is an outstanding post and for photographers with limited experience it helps to open the door for some experiments and growth in their photography. This is really great for the UHH.

johngault007 Loc: Florida Panhandle

Paul,
Excellent discussion on DoF with beautiful examples to go along with it.

CHG_CANON Loc: the Windy City

Thank you Dr J, Country Boy, Tony! I don't shoot wide open very much. The f/3.5 results of these lilacs from about this time last year had me consider why / why not. I wrote this up waiting for Spring to arrive again. Glad you enjoyed the images and ideas.

Cwilson341 Loc: Central Florida

This is educational and a thoughtfully put together demonstration. Very well done.

joecichjr Loc: Chicago S. Suburbs, Illinois, USA

No matter the settings you choose, they're awesome 🥇🥇🥇🥇🥇💕

Hereford Loc: Palm Coast, FL

Excellent well described tutorial on depth of field. I for one enjoyed and needed it.

lnl Loc: SWFL

Very interesting and a good lesson. Thanks for sharing your expertise.
Ellen L

Elias Amador

Thank you for the refresher course on d.o.f. By clicking on the right arrow the photos continued into ?your extensive collection of Chicago photos. As my family comes from Chicago, for me this was a great way to revisit the city. I particularly liked the photo of the Canal St railroad lift bridge, now well over a century old, and in sore need of some TLC.

Umnak Loc: Mount Vernon, Wa.

Thanks so much Paul!! While I feel like I have somewhat of a handle on the topics you discussed, it is so very helpful as I continue to hone my skills in varied types of photography. On that note, it's one the biggest draws for me on this forum/site. Very experienced people, like you and so many others, sharing what they have learned and most everyone just trying to help those that are attempting to become skilled in the wide world of photography!
Well done, said and portrayed my good sir!!
Rob

CHG_CANON Loc: the Windy City

Thank you Carol, Joe, Hereford, Ellen, Elias, Rob! As we enter the Spring / Summer season and flowers and insects, hopefully this discussion gives some ideas. Glad to help and share.

SENG

Thank you for sharing your knowledge and photos. I am still slow and uneasy while trying to capture macro images. Your information is helpful to me and your photos are a great demonstration of what you are teaching. I tend to have too much in focus and nothing really stands out or jumps into view as your photos did. It is both fun and frustrating to capture the close up beauty of flowers and insects. Thank you once again.

CHG_CANON Loc: the Windy City

Thank you SENG! If you have a tripod, one way to get a natural 'feel' for DOF and aperture is to just walk the lens from widest to smallest aperture with the same subject and distance. Just naturally focus, frame and shoot in aperture priority, take first what you think the aperture should be. Then, just adjust the aperture and let the camera adjust the shutterspeed. Look at the images in detail on your computer and make mental or physical notes of what works.

One of the things I really try to accomplish is picking where to focus. I use selective focus, typically with just one AF point. As you get to wider apertures and narrow DOF, it gets more important to decide where to focus. I mostly try to pick the point closest to the camera. In very close macro, sometimes the closest point isn't the best point for the composition. You have to experiment and critically review your results, repeating what works and avoiding / correcting what didn't.

SENG

Thank you, that sounds like a very good way to get a handle on the images. I will give that method many tries.