Are you Focusing Correctly?

Nigel Danson

12 Nov 202317:10

EducationalLearning

32 Likes 10 Comments

TLDRIn this photography tutorial video, Nigel explains key concepts related to focus and sharpness when using different focal lengths. He covers depth of field, finding the sharpest aperture for your lens, diffraction, and hyperfocal distance. Nigel then demonstrates real-world examples out in the mountains, showing when you can simply focus on infinity vs when you need to focus stack multiple images - which he says is less often than people think. He shares tips for tricky scenes with foreground elements, and shows a simple method for focus stacking in Photoshop to get front-to-back sharpness.

Takeaways

😀 Depth of field is less at longer focal lengths for a given aperture
🌟 Know the sharpest aperture for your lens from resources like DXOMark
📐 Acceptably sharp is not sharp enough, aim for true critical sharpness
🔭 Hyperfocal distance alone does not give the greatest depth of field
⚙️ Diffraction softens images at small apertures like f/22
🤔 Decide whether to stop down, get closer, or focus stack for full sharpness
👀 For distant subjects, focus anywhere and use optimal aperture
🖼️ Careful focus stacking requires overlapping sharp regions
✂️ Use layers and masks in Photoshop for basic focus stacking
🏞️ Compromise sharpness if required to get the desired composition

Q & A

What are some key things to understand about depth of field?
-Depth of field is affected by focal length - a longer lens will have less depth of field. Aperture also impacts depth of field - smaller apertures (higher f-stop values) increase depth of field. Defraction, which causes images to be softer, happens at very small apertures like f/22.
What is the sharpest aperture for most lenses?
-Most modern lenses are sharpest when shot just slightly stopped down from wide open, around f/4-f/8 depending on the specific lens. Shooting wide open or at very small apertures like f/22 will cause images to be less sharp due to optical issues.
What is acceptably sharp and why is it problematic?
-Acceptably sharp means an area of the image is reasonably sharp but not tack sharp. Relying on 'acceptably sharp' areas can be problematic because it does not result in images being as crisp and clear as they could be.
What is hyperfocal distance and how can you use it?
-Hyperfocal distance is the closest focusing distance that keeps everything from that point to infinity acceptably sharp at a given aperture. While it can be useful for maximizing depth of field, relying solely on the hyperfocal distance still may not render everything tack sharp.
When would you need to focus stack images?
-Focus stacking, where you combine multiple images focused at different distances, is necessary when you have a very close foreground object and want to get both it and the far background sharply in focus. This goes beyond depth of field from a single shot.
How can you simplify focus when shooting with a longer lens?
-With a longer lens like 70mm, you typically don't need to be as precise with focus since depth of field differences at longer focal lengths are less apparent. In this case, just focus anywhere in the scene and use the sharpest aperture for the lens.
What should you consider when focus stacking?
-When focus stacking, make sure your focus points have some overlap between images. Also shoot more images for complex scenes with objects sticking out at varying distances. Finally, align the images properly before masking and blending.
How can shot composition impact your focusing?
-Including very near foreground objects can make focus more challenging. Try to ensure a gradual transition from foreground to background distance when possible, rather than objects suddenly sticking out.
What basic steps are involved in focus stacking?
-Focus stack by taking multiple photos focused at different distances. Import into Photoshop, align layers, create a mask on the top layer, and use a gradient to gradually transition between the two layers' areas of sharp focus.
How can you create a focus stacked image?
-Take one image focused on the foreground and another focused further back. Import into Photoshop, align the layers, create a mask on the top layer, use a gradient transition on that mask. Adjust the gradient transition point until sharp areas are blended smoothly.

Outlines

00:00

🎥 Intro to video on focus techniques

The paragraph introduces the video, which will explain techniques for proper focus at different focal lengths from 16mm to 70mm. It covers things that affect focus and sharpness, as well as focus stacking. It thanks Squarespace for sponsoring.

05:00

💡 Basics of depth of field and sharpness

The paragraph explains key terminology related to focus. It covers how depth of field relates to focal length, the sharpest aperture for lenses, what "acceptably sharp" means, and diffraction when stopping down the lens aperture.

10:02

🌄 Shooting wide landscape scene

The paragraph shows an example of shooting a wide landscape scene while hiking up Helm Crag in the Lake District. It explains that with nothing in the foreground, you can just focus on the background at f/8-f/11 and everything will be acceptably sharp.

15:02

🗻 Focusing on closer foreground rocks

The paragraph continues hiking up Helm Crag and finds some rocks to photograph that are closer in the foreground. It explains options for getting sharp focus with wider depth of field or focus stacking.

⚡ Using longer lens with mountains

The paragraph shows an example using a longer 24-200mm lens to photograph mountains in the distance. It explains that at longer focal lengths, you worry less about depth of field and more about finding the lens' sharpest aperture.

🌉 Focus stacking close foreground rock

The paragraph photographs a large foreground rock that requires focus stacking at 16mm to get full sharpness. It shows focusing on near and far points and blending later in Photoshop.

Mindmap

Keywords

💡depth of field

Depth of field refers to the area in front of and behind the focal point that appears sharp and in focus. The video explains that depth of field is narrower when using longer focal lengths. For example, 'if you have a longer lens you've seen it when you’re shooting birds or something like that at 200 mm then you focus on the bird even at f8 there's going to be less depth of field than if you do a 24mm'.

💡aperture

The aperture setting controls how wide the lens opening is to allow light in. The video advises finding the optimal aperture for your lens that produces the sharpest images, which is often close to wide open rather than at the minimum (f/22) or maximum settings which can cause image softening.

💡acceptably sharp

"Acceptably sharp" refers to an area of the image having reasonable but not necessarily maximum sharpness. The video argues you should aim for more than just acceptably sharp focus across important areas of the image.

💡hyperfocal distance

The hyperfocal distance is the closest focus distance that keeps objects at infinity in acceptably sharp focus. However, the video notes that aiming for acceptably sharp focus does not lead to optimal image sharpness.

💡diffraction

Diffraction causes image softening at small lens apertures like f/22. This can cancel out the depth of field gains. There is often an optimal mid-range aperture sweet spot balancing depth of field against diffraction.

💡front to back sharpness

Getting front to back sharpness ensures critical near and far objects are pin sharp through focus stacking multiple images focused at different distances.

💡focus stacking

Focus stacking combines multiple images focused at different distances in post processing to maximize front to back image sharpness across all important areas and objects in a scene.

💡continuous drop off

Having a continuous drop off of focus between foreground and background objects makes focus stacking easier by ensuring overlapping sharpness transition zones.

💡defocus overlap

When focus stacking you want your near and far focused images to have a defocus overlap zone where both show reasonable sharpness for seamless blending.

💡focus blend

Focus stacking uses layers and masks in Photoshop to selectively blend the sharp zones from multiple images focused at different distances into a single final composite.

Highlights

Lenses have more depth of field at wider focal lengths compared to longer focal lengths

Know the sharpest aperture for your lens, usually slightly closed down from wide open

"Acceptably sharp" doesn't mean super sharp, you can get sharper than acceptably sharp

Hyperfocal distance isn't good enough, don't use "acceptably sharp" as your standard

Diffraction causes images to get softer at very small apertures like f/22

At wide focal lengths with distant backgrounds, just focus on the furthest object

When shooting landscapes, consider focus stacking to maximize front-to-back sharpness

With longer lenses, focus less on depth of field and more on using the sharpest aperture

Avoid sudden jumps between near and far focus distances when focus stacking

Use gradient masks in Photoshop to smoothly transition between focus stacked layers

Align layers first before masking when focus stacking to ensure accurate blending

Focus stacking combines two photos focused at different distances for front-to-back sharpness

Mask opacity transitions focus stacked layers from all top layer to all bottom layer gradually

Fine tune masked layers, play with opacity to get smooth transitions when focus stacking

Focus stacking gives you really pin sharp images front to back, much better than acceptably sharp

Transcripts

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