A 24× zoom in millimeters (mm) means the lens magnifies subjects 24 times between its widest and longest focal lengths, typically in a 35 mm equivalent range of 25–600 mm
What's Happening
Camera zoom is expressed as a multiplication factor (24×) and in millimeters (mm), where the 35 mm equivalent range describes how the lens performs on a full-frame camera
Ever wonder why camera specs list something like “25–600 mm (35 mm equivalent)”? That’s your lens’s full zoom range. The 25 mm end gives you a wide-angle view, while 600 mm pulls distant subjects in tight. The 24× ratio comes from dividing 600 by 25. (Yes, it’s that simple.)
Now, here’s the catch: smaller sensors like Micro Four Thirds or APS-C don’t capture the full image circle. They crop the edges, which effectively extends the focal length. So a 25–600 mm lens on a Micro Four Thirds body acts more like 50–1200 mm — turning that 24× zoom into a 48× zoom in 35 mm terms. Handy to know, right?
How to Read Your Camera’s Specs
To find your camera's 35 mm equivalent zoom range, check the settings menu, lens barrel, or EXIF data for a range like “25–600 mm (35 mm equivalent)”
Want to see your camera’s actual zoom range? On Android 15 or newer, head to Settings > Camera > Advanced. iPhone users running iOS 18 can open the Camera app, tap the little arrow (^) in the top-right corner, then go to Camera Settings > Zoom Range. You’ll see the wide and telephoto focal lengths listed there.
With DSLRs or mirrorless cameras, just look at the lens barrel. You’ll usually find two numbers separated by a hyphen, followed by “mm (35 mm equivalent).” If the spec sheet only says “optical zoom: 24×,” that’s a clue it’s probably a 25–600 mm range — but don’t take my word for it. Snap a test shot and check the EXIF data to be sure.
Step-by-Step Solution
If your camera doesn’t display the 35 mm equivalent values, calculate the zoom ratio by dividing the longest focal length by the shortest, using either lens markings or EXIF data
No automatic readout? No problem. Grab your lens and find the shortest and longest focal lengths. They’re usually printed near the front element or inside the battery compartment. Can’t find them? Take a photo at both ends, then open it in an EXIF viewer like Exif Viewer to read the exact focal lengths.
Once you’ve got the numbers, divide the longest by the shortest. Say it’s 600 ÷ 25 — that’s your 24× zoom. But here’s a pro tip: always shoot in “Optical Zoom Only” mode to avoid digital trickery. On Android, that’s Settings > Camera > Zoom > 0.5×–10× only. On iOS, look for Settings > Camera > Focal Length. This keeps you from accidentally using digital interpolation, which softens your images.
If This Didn’t Work
If your camera only offers digital zoom or confusing focal length labels, measure the real optical zoom using the lens barrel or EXIF data and account for crop factors
Some cameras don’t have a true zoom lens — they just crop the image in software. That’s digital zoom, and it’s terrible for quality. How do you tell? If the zoom ratio stays the same when you view the image on a computer, you’re dealing with digital zoom. (Not great.)
Crop sensor cameras need extra math. On Micro Four Thirds, multiply the focal length by 2× to get the 35 mm equivalent (25 mm becomes 50 mm). APS-C users multiply by 1.5× (25 mm becomes 37.5 mm). Adjust your calculations before you calculate the zoom ratio. Honestly, this is the best approach to avoid surprises.
Smartphones sometimes cheat, too. Some use two fixed lenses — say, 13 mm and 70 mm — instead of a true zoom. In that case, the 24× label is just software magic, not real optical range. Always double-check with EXIF data.
Prevention Tips
| Issue |
How to Avoid |
Frequency |
| Confusing digital vs optical zoom |
Always shoot in “Optical Zoom Only” mode (Settings > Camera > Zoom > 0.5×–10× only). |
Every time you shoot |
| Miscounting the zoom ratio |
Take a photo at the widest and longest settings, then check the EXIF data in an image viewer to read the focal lengths directly. |
Once per new lens or phone |
| Using the wrong aspect ratio |
Set the camera to 4:3 for accurate lens spec sheets; switch to 16:9 only for final delivery to avoid cropping. |
Edited and fact-checked by the TechFactsHub editorial team.
