Sharpness

[terri33inne]

I'm new, and wasn't sure where to post this question... I hope this is the right spot.

I'm on a quest to figure out how to make my pictures sharper... I see other photos that just amaze me, and I can't figure out how they get them so sharp... is it a filter? Post-processing? I feel confident in my abilities with composition but for some reason my photos just don't have that look... The only PP software I've ever used is Picasa which is limiting but fits my needs as a hobbyist... I'm dipping my toe into portraits for $ 1st shoot next week.

I shoot a Pentax k10d, and my favorite lens is a 50mm 1.4 b/c of it's abilities in low light.

So, how do you get your photos tack sharp?

[photocoursesuk]

Its all about the lens, I used to have a Canon 30D and had the same query. I was thinking about upgrading my camera as the images were not sharp. I then used my friends lens and could't belive the results.

I was using cheaper low end lenses, the lens I borrowed was 3x the price of my most expensive lens.

Now I would rather invest in lenses rather than cameras.

Go to your local photography store, they will be happy to let try their lenses with your camera.

[sma200]

You didn't list what lense you started using... I also have a canon, and have the same issue.

[BigVinnie]

Right or wrong this is what I came up with:

Post on my blog about sharpness.

I have a Canon XSi. The pictures on the blog post were taken with a 17-85 EF-S IS USM lens.

[zona5101]

A good, sharp lens is essential...but a lot of people enhance the sharpness in post processing. Techniques such as "unsharp mask" and high pass filtering are very common.

[kencaleno]

Originally Posted by terri33inne

I'm new, and wasn't sure where to post this question... I hope this is the right spot.

I'm on a quest to figure out how to make my pictures sharper... I see other photos that just amaze me, and I can't figure out how they get them so sharp... is it a filter? Post-processing? I feel confident in my abilities with composition but for some reason my photos just don't have that look... The only PP software I've ever used is Picasa which is limiting but fits my needs as a hobbyist... I'm dipping my toe into portraits for $ 1st shoot next week.

I shoot a Pentax k10d, and my favorite lens is a 50mm 1.4 b/c of it's abilities in low light.

So, how do you get your photos tack sharp?

(From my Book)

Focus

Is the measure of the degree of sharpness in our images.
All modern cameras have Auto-focusing, which works very well, but there are times when you need to focus manually. For auto-focus to work properly it requires a certain amount of contrast, if the contrast isn’t adequate you will need to focus manually.[ NOTE: In your camera’s viewfinder, depending on camera-flagship models generally have many focusing spots, and lesser, entry-level dslr’s will have around 5 focusing spots. With lens wide open, any of these spots can be used for selecting where to auto focus-But, depending on maximum aperture of lens in use, the ones you are able to use get fewer. Top-of-the-line cameras will only have the centre spot usable at F8,and entry level cameras at F5.6, and less than that, even these single spots aren’t reliable.]
Actually it is more beneficial to set auto focus by the centre spot, then re-compose, rather than use the peripheral spots-The reason being that only the centre spot has vertical and horizontal pixel rows. This means that if you use the peripheral spots (top and bottom spots have horizontal pixels only and right and left spots have vertical pixels only) To focus, you must have a part of the scene crossing a line of pixels at 90 degrees, and the centre spot gives you a more accurate reading ,having both vertical and horizontal pixels) It will pay you to manually focus most of the time, for full control of the situation. For instance, if an unnoticed reed encroaches into your image, when your are shooting a swan at the lake, for instance, your lens may auto-focus on that reed, rendering your actual subject out of focus.

Concerning Auto focus

There are times, you will find when auto focus will fail to respond favourably-although auto focus is able to lock on to any subject, there are certain conditions where it may not be possible ,even when the indicator lights are on, and the shutter releases.

Subjects with low contrast
Solution: Focus on something the same distance as the subject you want to make an image of, then aim at that subject
Subjects in excessively bright light
Solution: Focus on something the same distance as the subject you want to make an image of, then aim at that subject
Two subjects at differing distances
Solution: Focus on something the same distance as the subject you want to make an image of, then aim at that subject, and re-compose
Subjects with repetitive patterns
Solution: Focus on something the same distance as the subject you want to make an image of, then aim at that subject, and recompose
High speed subjects at close range
Solution: focus on another subject at the same distance-to-subject distance first, then re-compose your frame
To ensure you are in focus, there, in the viewfinder, is the electronic rangefinder icon, that comes on when you are in focus. NOTE: Each lens has its “sweet-spot”, that is when the aperture and zoom length combine to give optimum sharpness- 18-55 mm zooms usually have this “sweet-spot” at the 35mm distance setting and 2 stops back from wide open. On a 70-300mm zoom the “sweet-spot” would be around 185-200mm aperture 2 stops back from widest.
Auto focus is good for situations where you cannot focus fast enough, manually, such as sports and wildlife photography.
Depth of field appears to be the most confusing of focus elements. Depth of field is a range of acceptable sharpness in an image, from near to far. Three factors control Depth of field: Aperture: The wider the aperture, the shallower the depth of field. Focal length of lens, The longer the focal length of the lens, the shallower the depth of field will be. and Distance from subject, Landscape images have great depth of field, whereas Macro (extreme close-up) images have very shallow depth of field. Concerning depth of field, Hyperfocal distance seems to be even more confusing -Hyperfocal distance is a point of focus where at a certain aperture, Half the distance from that point to Infinity, (which starts at 30 feet, and extends to as far as you are able to see)) will be in acceptable focus, The best lenses for hyperfocal distance are 80mm or wider ; telephoto lenses, because of their relative short depth of field, are rarely used. (Prime lenses have a scale on them for this, zooms do not) Using a 18mm setting on your zoom lens at f11, Hyperfocal distance is somewhere around 5 feet (1500mm), so depth of field at this aperture would be from 2 1/2 feet ( 750mm) to infinity, when focused at 5 feet. A good guideline for great depth of field for landscapes is to use the bottom focusing marker in your DSLR viewfinder, (either horizontal, or vertical) as this will focus 1/3 of the way into the distance, (It is on the lower third imaginary “Rule of Thirds” gridline!) ,as is usually recommended. [ NOTE: Unless your camera has depth of field preview, looking through the viewfinder all will not be in focus, because your lens, until you press the shutter button to make the shot, will be open at full aperture.]

[RichardTaylor]

It is all about contrast and the variables are:

(1) The subject itself - is it a subject that has texture or smooth like a rose petal.

Example - here we have both

Camera Canon PowerShot G11
Exposure 0.1 sec (1/10)
Aperture f/3.5
Focal Length 13.8 mm
ISO Speed 200
Exposure Bias 0 EV
Flash Off, Did not fire

(2) Lighting - is it straight on or from an angle to enhance the textures

Example - also pic has been PP'd to give it that "industrial" look.

Camera Canon EOS 5D
Exposure 0.04 sec (1/25)
Aperture f/6.3
Focal Length 24 mm
ISO Speed 1600
Exposure Bias +1/3 EV
Flash Off, Did not fire

(3) Camera/lens performance - how good is the lens and camera and any filters? Are you using a lens hood?

(4) Shooting technique - are you shooting at high enough shutter speed, or panning, to prevent camera & subject motion? Are you shooting at an aperture that will isolate the subject, and/or at the sharpest aperture, and/or provide great DOF. What are you focussing on? Are you using a tripod?

Example - high shutter speed + wide-ish aperture + a bit of selective blurring & sharpening in PPing.

Camera Canon EOS 40D
Exposure 0.001 sec (1/1600)
Aperture f/8.0
Focal Length 400 mm
ISO Speed 400
Exposure Bias -2/3 EV
Flash Off, Did not fire

Example 2 - Shallow DOF , and dark background to provide contrast for the flowers. also shot with a high quality prime lens.


Camera Canon EOS 40D
Exposure 0.001 sec (1/1000)
Aperture f/2.0
Focal Length 135 mm
ISO Speed 400
Exposure Bias -1 EV
Flash Off, Did not fire



(5) Post processing - adjusting contrast and/or adding "grit" and finally sharpening for the intended medium.

Hope this helps.

[terri33inne]

Thanks everyone... Shouldn't the 50mm produce sharp images? I did find a Vivatar 85mm lens that's compatible w/ Pentax... should I consider that?

This photo of my daughter is in focus, but still doesn't have that look that I see from so many photographers. It was taken outside late afternoon sun.

[IMG][/IMG]

Lens 50mm
Exposure 1/2000
Ap 2.8
ISO 400

[RichardTaylor]

(1) Not much DOF at 50mm & F2.8 (about 2" of you were about 4 feet away). Try shooting at around F8. I think this is the biggest problem

(2) What direction was the sunlight coming from?.

(3) I wouldn't be shooting at ISO 400, I would be at a lower ISO if possible. You have a lot of leeway with your shutter speed so high.

(4) Was the pic shot in raw and sharpening applied during PPing or is it a (almost straight out of the camera) jpg?

[BigVinnie]

I don't see any issues with the sharpness of that image.

I think your issue may be more of one of lighting. It is very flat and has nothing to help with texture. A little bit of side lighting goes a long way.