Focus Stacking

[ChrisH]

I have been aware that quite a number of my landscape images appear quite sharp around the middle, but soft either side particularly at the top. I therefore asked "Google" for help and came up with Focus Stacking (C in C also has a good tutorial on this subject).

The first image was taken using automatic focus (as a control).



When blown up you can see the church spire and the buildings near the bridge are soft, although the centre of the scene around the narrow boat is sharper.



Now the picture is sharp from top to bottom. Neat eh?

[Shadowman]

What lens were you using or was this stitched together?

[Polar01]

Just two questions, as you were using AF where were you focusing and what f-stop was used?

Cheers: Allan

[FrankMi]

Nice scene Christopher! Focus Stacking isn't just for close-ups but really for any situation where you need to increase the DoF beyond what the appropriate camera settings can provide for the scene. Some cameras, like my Canon SX40, have a three exposure focus bracketing built in just for this purpose.

[Downrigger]

Very nice. I'm wondering what part of the experiment yielded the nicer light seen in the second shot - the focus stacking itself, or additional PP?

[Ken Curtis]

Hi Christopher.

I looked at your top image and it was taken with an aperture of f4 and a focal length of 20 mm. I am surprised that you did not use a smaller aperture, say f11 or f16 to improve the depth of field.

In the second image, the EXIF data say that you used f10 and 21 mm, so I would expect a sharper image with the smaller aperture.

I admit that the focus stacking worked well for you. Focus stacking can be a problem when the objects are moving, and I am curious how you got the birds and ripples in the water so clear.

[ChrisH]

Sorry to take so long to respond.

John - I used a Canon EF 17-40mm 1:4L without stitching.

Allan Short - I used manual focusing 1) around the birds 2) the narrow Boat 3) the Church Spire. f/10.0

Frank - Unfortunately my Canon 30D does not appear to have Focus Bracketing, so until I buy a new camera I have to do it manually. Another good reason to buy a new camera!

Mark - I did edit the light in PS.

Ken - Sorry about the test shot. I just fired it of without checking the settings.

The birds are a bit of a mystery. The time between the first and last exposure was 17 seconds so you would expect some serious movement. I used Photoshop CC to do the stacking and just wonder if this program detected the movement and eradicated it.

Thanks for all your replies.

[FrankMi]

The birds are a bit of a mystery. The time between the first and last exposure was 17 seconds so you would expect some serious movement. I used Photoshop CC to do the stacking and just wonder if this program detected the movement and eradicated it.

If CC is like CS5, when you look at the masks created by the Auto-Blend, you will be able to see what parts of each image were used. Auto-Blend will use bits from only one of the images for each selected area and tries to get the bits that are the sharpest from each image. If the birds didn't have a sharper appearance than the water from another image, they won't necessarily appear in the final mosaic. On the other hand, the process isn't perfect and if you pixel-peep you may find sharper bits in a selected area of an image that were not chosen. If you are fussy and patient, you can go back and blend in some of these sharper bits.