There are two focal lengths I rely on most when photographing food, 50mm and 85mm (on a crop body these two lenses act more like 85mm and 135mm lenses respectively – both great focal lengths for food as well). Even if I’m not shooting primes, I will by default choose something near 50mm or 85mm on a zoom lens. (Can you guess which of the two focal lengths was used for the image above?)
So, which is better? What are the differences between these two focal lengths? 35mm difference may not seem like a lot but it is. And if you’re shooting on a crop body, then the difference between the two lenses is closer to 50mm.
With the exception of focal length and the physical placement of the camera in relation to the subject (working distance), all other settings are exactly the same in these images. In addition to that, the objects in the frame (foreground – pickle, midground – burger, and background – beer, stack of bread, pickle jar and onion) are never moved throughout the shoot.
Camera: Canon 5D MkII (full frame)
Shutter speed: 1/60
Subject to Background: 3′
Subject to Camera: Variable
Using different focal lengths will affect depth of field and perceived perspective compression (or the perceived distance between objects with in the frame). Objects in the background can also appear to change size with different focal lengths. Exposure, color and contrast are not affected by focal length (though will vary from one lens to another).
Focal Length Comparison
Here the framing is identical, which required a working distance of 1’6″ with the 50mm lens and 3′ with the 85mm lens. As you can see, the foreground and background objects in the 50mm photo appear farther away from the subject in focus. They also appear closer to each other (notice we see more bread and a little bit more beer in the 50mm image).
The more telephoto lens here (the 85mm) compresses the space more than the 50mm (this is only the case when you adjust the working distance so that the framing remains the same). Assuming framing is the same, longer focal lengths will compress or squish depth in the photo. It can also push them farther to the side of the frame, making them less distracting to the subject.
This image is shot straight on.
Here is another image, shot at a higher angle to help show the difference in object compression from foreground to background. Notice how much father away the background objects are. You can notice a big difference in the pickle too.
You will also notice the depth of field is slightly narrower on the 85mm (even though the aperture is the same). Because the 85mm has a narrower angle of view than the 50mm, it will create a shallower depth of field at identical camera settings.
Identical Working Distance
Working distance is the distance from the subject of the image to the camera lens (technically to the sensor inside the camera). Here the cameras are both 3′ away from the subject. With this photo, we obviously see a huge difference in framing.
Here the images are not cropped. Wider lenses let you capture more when shooting at similar distances. This is helpful for small spaces when you don’t have a lot of space to move around.
Identical Working Distance & Framing (requires cropping)
While the working distance of both lenses is the same, the 50mm image is cropped so that the framing is identical to the 85mm.
Crop the photos so they appear to be framed the same way and we now notice that with the camera in the same place, there is no affect on compression. That’s right, lenses do not affect the perspective compression of objects within a photo. Your working distance does. That being said, it’s not practical to shoot at the exact same distance from a subject across various focal lengths, nor is is practical to use one focal length for a number of subjects. This is why we buy lenses with varying focal lengths. And this is why we associate perceived perspective compression with different focal lengths.
The cropped 50mm photograph is also representative of what it is like shooting a 50mm lens on a crop body. As you can see, a 50mm on a crop body essentially becomes an 85mm. Shooting on a crop body will thus affect both the perceived perspective compression of a lens and the working distances required.
Why Choose One Over the Other
While you should consider various factors like a lenses speed (maximum aperture), it’s color, saturation and contrast rendition, and the lens’ ability to handle flaws such as light fall off, edge softness and Chromatic Aberration when choosing a lens, the most important factor should and will likely be focal length.
The two biggest reasons to choose one focal length over the other are perceived perspective distortion and working distance. If you have a small kitchen and shoot on a crop body, it might not be practical to get an 85mm as you will need to be 6′ + away from the subject you are shooting. Of course, If you want beautifully compressed images with shallow depths of field, then the 85 (or longer) may be perfect for you.
So, which do I prefer? While it depends on what I’m shooting specifically, I typically prefer 85m in food photography. I like the shallower depth of field and compression you get out of the lens. That being said, if you’re shooting on a crop body, I’d suggest the 50mm as the working distance on the 85mm becomes cumbersome (around 6′ for shots like these).
Full Frame vs. Crop Body
The images in this post were shot on a full frame sensor (Canon 5D Mk II). If you shoot on a crop-sensor (such as those found in the Canon 7D, 60D, T4i, etc) then you will need to multiply the lens’ focal length by 1.6 (or 1.5 for Nikon) to determine the effective focal length.
This diagram shows how the size of a camera’s sensor affects the image it captures. APS-C sensors, or crop body sensors, are smaller than 35mm or full frame sensors, so in effect lenses mounted on a crop body act as a telephoto version of themselves on a full frame sensor. To determine the effective focal length of a lens on a crop body, simply multiply the focal length by 1.6 (or roughly 1.5 if you use a Nikon).
What does this mean for shoot? All it means is your working distance between the camera and your subject may be different. Where as with a 50mm I was 1′ 6″ away from the subject, on a crop body you may need to be 3′ away. With an 85mm lens, a full frame working distance of 3′ is pushed back to a quite far 6′ on a crop body.
Full frame sensors (since they are larger) will produce shallower depths of field with the same settings and focal lengths used on a crop body.
So, did you guess which lens I used for the first image in this post? Yep. It was shot on the 85mm (Canon’s 85mm f/1.8). What is your favorite focal length for food photography. Share it and your favorite food photos in the comment section below!