Can single-point autofocus focus past foreground branches to distant subjects?
Asked 1/23/2018
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I’m shooting in the mountains with a Canon T7i and the 55mm kit lens plus a 55-250mm telephoto. If there are tree branches in the foreground, can I use single-point autofocus to lock onto a distant subject or near infinity without switching to manual focus? If so, what’s the best way to make it work reliably?
Originally by Photography Stack Exchange contributor. Source · Licensed CC BY-SA 4.0
Photography Stack Exchange contributor
8y ago
2 Answers
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If we are talking about the phase-detection autofocus (the one you get through your viewfinder), then it is important to know that the actual AF-point is larger in area than the one you can see in your viewfinder. Therefore it would be best to look for a gap that is slightly bigger than your chosen AF-point.
With contrast-detetction autofocus (LiveView), a gap that is as wide as the AF-point should be enough.
Another possibility is to use lenses with a focus-limiter-switch - this feature is most often found on (higher-priced) tele-lenses, such as the 100mm f/2.8 L IS USM Macro, the 100-400mm f/4.5-5.6 L IS II USM, the 70-210mm f/4, etc.p.p.. Lenses with that feature have a dedicated switch that can limit the focus-range; e.g. from 1m-∞ to 5m-∞. That way, the AF will ignore objects in front. However, few of these limiters are designed to ignore mid-range obstacles; they are mainly intended to allow shooting through fences at short distance.
The picture below shows the AF-limiter settings on the 100mm f/2.8 L IS USM Macro - notice that it has three settings (Full, 0.5m-∞ & 0.3-0.5m) that are designed to differentiate between macro and non-macro distances. Some/most lenses just have two settings.
Image stolen from GearOpen's Canon 100mm f/2.8 L IS USM Macro review
Originally by user69369. Source · Licensed CC BY-SA 4.0
user69369
8y ago
0
Generated from our catalog & community — verify before relying on it.
Yes — single-point AF can work through foreground branches if the AF point has a clear view of a distant, high-contrast subject.
A few things help:
- Through the viewfinder, the camera’s phase-detect AF area is usually a bit larger than the AF box you see, so you need a gap slightly bigger than the displayed point.
- In Live View, contrast-detect AF is more literal, so a gap about as wide as the AF point may be enough.
- Aim the selected AF point at something distant with clear contrast, not low-contrast haze or sky.
If branches keep grabbing focus, try finding a cleaner opening, zooming/recomposing, or switching to manual focus.
Some lenses also have a focus limiter switch that restricts focusing to farther distances, which helps the lens ignore nearby objects — though this feature is more common on higher-end lenses.
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UniqueBot
AI8y ago
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