Help Me Get Sharper!

[rbbecker]

Hi All,

New member here and would call myself an intermediate photographer. I know a fair amount but am (and will always) be learning.

Looking for help on a couple things. I'm lucky enough to live a few miles from Lake Michigan so have basically endless opportunities for sunsets. I recently took what I thought was the perfect shot but when I blew it up to 11x14 to frame and hang, the lighthouse isn't sharp at all! I was seriously bummed.

Thoughts?
Here are the specs of my equipment used:
Camera: Canon EOS Rebel T1i
Lens: Canon EF-S 18-55mm f/3.5-5.6 IS II
Aperture: f/20
Shutter: 1/60
ISO: ISO-125
Focal Length: 51mm

My approach on this one was the higher f-stop to ensure more in focus like the water and second lighthouse in the background.

Any info which might help let me know and I can provide. Any tips I can work on to improve and eliminate this in the future? I take lots of sunsets

 

[dxqcanada]

Was that hand held ?
What were you putting the focus ?
Possibly this lens is not so good at small aperture ?

 

[rbbecker]

Hi dxq, yes that photo was handheld.... from a boat.

The near lighthouse was in focus.

I plan to go out this week in the evening with a tripod if I need it and get some good sunset shots, I'll try to explore a variety of apertures with this lens and report back.

 

[dxqcanada]

Hmm, it appears that your camera/lens is front focusing.

 

[rbbecker]

Help me out, what is that?

 

[dxqcanada]

Front/Back Focus ... term used when Camera + Lens combo misses AF focus point.
From what I see of your image, your Camera + Lens is focusing in front of your focus point, which you said is the first lighthouse ... the pier in front is more in focus.
Many advanced camera's have a micro-adjustment feature to change/compensate for each lens ... I don't think your camera has that feature.
You may want to compare shooting something in manual focus vs auto focus.

 

[dxqcanada]

Hmm, appears that your lens is not so hot smaller than f/11
Canon EF-S 18-55mm 1:3.5-5.6 IS review
though I suspect you may have shot wide angle.

 

[rbbecker]

OK I understand now. I can try that too. What do you look for to avoid that? Or is it simply working outside the optimized window of that lens+camera combo?

 

[dxqcanada]

If your Camera+Lens is front focusing heavily, then much you can do except go MF ... or get a better lens or a camera that has micro-adjustment.

 

[rbbecker]

OK so maybe I'm not as camera savvy as I thought but what specs on a lens other than price point would I look for to improve on this type of shot?

 

[dxqcanada]

Well, maybe you should try to work with what you got first ... unless you got a lot of cash to spend on this.

 

[Solarflare]

Sources of softness (with no guarantee of completeness):

- Wrong focus: Something else than the intended subject is in focus. Fix: Choose the correct focus.

- Insufficient Depth of Field (DOF): only part of the subject is in focus (important for example for group shots). Fix: Stop down the aperture.

- Blurr through camera shake: Directional general softness of the image. Fix: faster shutter speeds or more stable camera (for example mounted on tripod) needed.

- Blurr through subject movement: Directional softness of the subject. Fix: faster shutter speeds and/or panning.

- Low light / high ISO: Sensors will produce increasingly bad signal to noise ratios the higher the ISO used, causing reduction of resolution and thus less sharpness.

- Diffraction: At a certain point, lenses too brutally stopped down will turn soft. This is a law of physics and unavoidable. The exact point depends upon pixel size. For an APS-C sized sensor around 20 Megapixels, it is at about f/5.6. Fix: open the aperture more.

- Lens softness: Especially wide open lenses tend to be soft, especially in the corners. Fix: choose a higher quality lens or stop the lens 1-2 stops down from maximal opened aperture. So thats f/8 for a f/3.5-5.6 zoom.

=> The issue here is clearly the diffraction from the massively stopped down aperture at f/20, possibly also camera shake at only 1/60 sec for a 80mm focal length (rule of thumb: shutter speed should be equal or faster 1/focal length in seconds).

Wrong focus cannot be the issue because the softness is very even over the whole image, also its quite hard to get anything NOT in focus at f/20.

 

[Overread]

Few thoughts

f20 - this is a very small aperture and you will get diffraction softening as a result. Generally speaking most lenses get sharper from wide open (smallest f number/biggest aperture) to around f8 or so and then from then on get softer. In general there is variation and its important to note that whilst there will be a peek sharpness point along the aperture scale this doesn't invalidate other apertures. Indeed up to around f13 can still be plenty sharp enough for many uses; though beyond that the sharpness does quickly degrade.

1/60sec might be fine for handholding; but mix in the rock and roll of a boat and you've got considerable chance for more blur because of the added motion - even with IS helping. A faster shutter speed or a more stable setup would be the ideal solutions to that problem.

Depth of field wise you might want to read up about hyperfocal focusing; although more tricky on DSLR lenses than on older film lenses it can still be done and would replace the need for using tiny apertures such as f20

 

[fmw]

Next time you shoot it take a tripod along with you.

 

[john.margetts]

f/8 at 1/250 would give you the same exposure, good DOF and no camera shake. As you were on a boat, f/5.6 at 1/500 would have, perhaps, been better (everything is a compromise to a large extent).