Depth of field question

[Drogo]

Today I was shooting a tree from a tripod using two different lenses.

Camera, Fujifilm XT10
Lenses, Fujifilm 18-55mm and 18-135mm

Both lenses were set at 18mm @ f22 but I seemed to be getting a much shallower DOF with the 18-135mm

What am I missing?

[GroundEffect]

Should be the same. Got sample images that you can re-take?

[DibblyDobbler]

As above - same sensor size + focal length + aperture should give the same DOF as far as I know.

Ps... why use f22 at 18mm ?

[Drogo]

Old Horse Chestnut by Dave King, on Flickr

Not sure if the image is any good but was trying auto spot focus on different parts of the trunk and branches after using manual focus as I wanted to try to do the old tree justice.
I changed to the 18-135mm as I've had confidence issues with the 18-55mm and saw the change in DOF via the EVF scale, above with 18-55mm.

DD
I was going for max DOF to be sure all was acceptably sharp.

Still may need a touch more processing.

[Super Slo Mo]

Thing is with such a tiny aperture you will lose sharpness as diffraction becomes a significant factor.
Try opening the lens up to F11 or F8 and see how they both compare.
Your DOF at 18mm should still be immense.

[Drogo]

I wasn't aware of that.
Maybe I'm trying to hard to get the most detail in the tree.

Will have to get out again tomorrow, thankfully the tree is only a ten minute walk from home.

Thanks Slo Mo

[JonChalk]

Super Slo Mo said:

Thing is with such a tiny aperture you will lose sharpness as diffraction becomes a significant factor.
Try opening the lens up to F11 or F8 and see how they both compare.
Your DOF at 18mm should still be immense.

This - I have to admit, I'd probably be going even wider than that in stages to see how much of the tree I could keep sharp, whilst blurring the background a bit, but that's not gospel, just personal choice. Keep experimenting to see what you lie.

I rarely use more than f13 anywhere, even for landscapes, this is the closest sort of thing I have to hand & this was at f2.4:

[Super Slo Mo]

This link explains diffraction reasonably well, better than I can using an iPhone anyway.
https://fstoppers.com/studio/fstoppers-original-wh...

Most lenses have a sweet spot for sharpness around the F8-F11 region. The better the glass, the wider the maximum aperture you can get without losing too much sharpness, it’s to do with how precisely the glass is machined.

[singlecoil]

Some of the OP's picture is quite close to the camera, and the rest of it some distance away. If you wish to compose a picture like that then you are going to have DOF issues. If you have access to decent post processing software then I suggest you take several shots at different focus points and use the software to align the images and then stack them.

[GroundEffect]

Super Slo Mo said:

Thing is with such a tiny aperture you will lose sharpness as diffraction becomes a significant factor.
Try opening the lens up to F11 or F8 and see how they both compare.
Your DOF at 18mm should still be immense.

That. Most lenses are their "most sharp" around F/4-F/8 range but you lose out some depth of field chasing the actual sharpness. Doing what you're trying to do I would limit myself to around F/14 at most. You start to get more colour fringing beyond it.

And having the whole scene as sharp as you can get it means you lose some depth to the shot...it'll appear flatter. Find the composition's natural focal point, and make that sharp.

Edited by GroundEffect on Wednesday 24th October 21:59

[checkmate91]

Hyperfocal app may help with distance-to-object and depth of field... nothing worse than setting it all up and getting the blade of grass in front of the object in focus...

[Drogo]

Thanks folks.

I was aware that most lenses are best at around f8-f11 but not the full reasons and maybe placing to much faith in Fuji lenses being top notch but had no knowledge of diffraction. Apart from trying to work out why I was getting so much purple fringing. :roll eyes: Obviously now the two go hand in hand.

Singlecoils, the F stoppers video helped a lot.
I also understand your suggestion of a focus stacking, I can try that as am using ON1 Photo Raw.

[Super Slo Mo]

Some more interesting reading

https://photographylife.com/what-is-chromatic-aber...

https://en.m.wikipedia.org/wiki/Chromatic_aberrati...

[Craikeybaby]

Does the X-T1 have the focus distance scale with depth of field bar, like the X-T2? If so that may help.

What issues have you been having with the 18-55mm lens? I've found mine to be really good.

[Drogo]

Yes, AFAIK all X series have the DOF bar.

Issues with the lenses are of my own making as still getting to grips with proper photography.
The X-T10 is so close in feel to my old Pentax ME Super I love it. I bought the 18-55 as it's quite a bit lighter than the 18-135 and I like to travel light but can't bring myself to sell the 18-135 yet hence the lens shaping during the tree shoot.

I really appreciate the help everyone on here gives but sometimes I don't know what I don't know.

I've getting inspiration from the guys on youtube that do landscape and woodland, Thomas Heaton and Gary Gough, Simon Baxter and others.

Previously just a holiday snapper and really want to put more effort into it. I also watch Mike Browne on youtube and find him a good teacher, maybe have to sign up to one or two of his courses.