Manual Focus Problem

[idcrewdawg]

I am having a manual focus problem with my 40D. I am currently using a sigma APG DG 70-300 1:4-5.6. Though I also seem to have a similar problem with my kit lens, it just doesn't seem to be as noticeable as my subjects are further away.

I took some photo's while on a recent vacation, and while they look sharp when fully zoomed out, when you zoom in you can see there is a slight bit of fuzziness on the subject of the picture. I've tried adjusting the dioptric knob in the viewfinder, and got it to the best results available. I still seem to have a focusing problem.

Here is one example...



And the same image zoomed in...



Admittedly I use glasses to read, but didn't for this photo. I realize this could affect my shots. With that in mind, I also use the auto focus blocks in the view finder to help me gauge when I'm close to being focused.

Other than wearing glasses during my shots can I fine tune the dioptric knob, or is there another way to calibrate the viewfinder to the lens?

[RoyL]

When adjusting the diopiter look through the viewfinder at a plain wall and adjust the wheel until you get the sharpest view with the center focus point (and ring if it has one). Should now be adjusted for your eyes. If you have done it this way and still have problems then you may need to get a higher magnification viewfinder.

[sk66]

I've found the depth of field at high magnification can be VERY thin...
Without exif I can't tell if there were any settings which might be off.

From just looking at the image I see the bird was moving; easy cause. It also appears the "focus" is just behind the bird, easy to do when using max aperture trying to make up for long focal length and lower ISO. And, it looks like a 100% blowup.....VERY few images will stand up to 100+% magnification...

[kencaleno]

Originally Posted by RoyL

When adjusting the diopiter look through the viewfinder at a plain wall and adjust the wheel until you get the sharpest view with the center focus point (and ring if it has one). Should now be adjusted for your eyes. If you have done it this way and still have problems then you may need to get a higher magnification viewfinder.

Detach lens, adjust dioptre (next to viewfinder) so central focus point is sharply in focus. ( Never mind anything else, the focus point in viewfinder must be sharp) Preferably against a white background. Re-attach lens.

regards, Ken

[kencaleno]

Originally Posted by sk66

I've found the depth of field at high magnification can be VERY thin...
Without exif I can't tell if there were any settings which might be off.

From just looking at the image I see the bird was moving; easy cause. It also appears the "focus" is just behind the bird, easy to do when using max aperture trying to make up for long focal length and lower ISO. And, it looks like a 100% blowup.....VERY few images will stand up to 100+% magnification...

When you are photographing for stock agencies,as I do, every shot must stand up to 100%+magnification. regards, Ken

[idcrewdawg]

The exif data is below. And just for the record, it was only 1:1 blow up.

When I take a photo, I'm looking to have it framed in nothing less than a 16X20 frame. If I can't enlarge it to that, I'm not satisfied with the shot.

I will try adjusting the dioptric as suggested, thanks for the advice!


_____

Exposure: 0.004 sec (1/250)
Aperture: f/5.6
Focal Length: 300 mm
ISO Speed: 100
Exposure Bias: 0 EV
Flash: Off

File Size: 2.8 MB
File Type: JPEG
MIME Type: image/jpeg
Image Width: 3888
Image Height: 2592
Encoding Process: Baseline DCT, Huffman coding
Bits Per Sample: 8
Color Components: 3
Orientation: Horizontal (normal)
X-Resolution: 72 dpi
Y-Resolution: 72 dpi
Date and Time (Modified): 2009:03:14 11:36:51
YCbCr Positioning: Co-sited
Exposure Program: Program AE
Date and Time (Original): 2009:03:14 11:36:51
Date and Time (Digitized): 2009:03:14 11:36:51
Metering Mode: Multi-segment
Sub Sec Time: 00
Sub Sec Time Original: 00
Sub Sec Time Digitized: 00
Color Space: sRGB
Focal Plane X-Resolution: 4438.356164 dpi
Focal Plane Y-Resolution: 4445.969125 dpi
Custom Rendered: Normal
Exposure Mode: Auto
White Balance: Auto
Scene Capture Type: Standard
Macro Mode: Normal
Self Timer: Off
Quality: Fine
Canon Flash Mode: Off
Continuous Drive: Single
Focus Mode: Manual Focus (3)
Record Mode: JPEG
Canon Image Size: Large
Easy Mode: Manual
Digital Zoom: None
Contrast: Normal
Saturation: Normal
Metering Mode: Evaluative
Focus Range: Not Known
Canon Exposure Mode: Program AE
Lens Type: Canon EF 100-300mm f/5.6 or Sigma or Tokina Lens
Long Focal: 300 mm
Short Focal: 70 mm
Focal Units: 1
Max Aperture: 5.7
Min Aperture: 32
Flash Activity: 0
Flash Bits: (none)
Zoom Source Width: 0
Zoom Target Width: 0
Manual Flash Output: n/a
Color Tone: Normal
Auto ISO: 100
Base ISO: 100
Measured EV: 8.25
Target Aperture: 5.7
Target Exposure Time: 1/256
White Balance: Auto
Slow Shutter: None
Sequence Number: 0
Optical Zoom Code: n/a
Flash Guide Number: 0
Flash Exposure Comp: 0
Auto Exposure Bracketing: Off
AEBBracket Value: 0
Control Mode: Camera Local Control
Bulb Duration: 0
Camera Type: EOS High-end
NDFilter: Unknown (-1)
Flash Output: 0
Canon Firmware Version: Firmware Version 1.0.8
Serial Number: 1620808963
Camera Orientation: Horizontal (normal)
Focus Distance Upper: 0
Focus Distance Lower: 0
Color Temperature: 5200
Firmware Version: 1.0.8
File Index: 385
Directory Index: 100
Lens Model: 70-300mm
Canon Model ID: EOS 40D
AFMode: Off (Manual Focus)
Num AFPoints: 9
Valid AFPoints: 9
AFArea Widths: 97 97 97 97 97 97 97 97 97
AFArea Heights: 98 98 98 98 98 98 98 98 98
AFPoints Selected: 0,1,2,3,4,5,6,7,8
Original Decision Data Offset: 0
Bracket Mode: Off
Bracket Value: 0
Bracket Shot Number: 0
Raw Jpg Size: Large
Noise Reduction: Off
WBBracket Mode: Off
WBBracket Value AB: 0
WBBracket Value GM: 0
Internal Serial Number: J0991552
Dust Removal Data: (Binary data 1024 bytes)
Tone Curve: Standard
Sharpness: 3
Sharpness Frequency: n/a
Sensor Red Level: 0
Sensor Blue Level: 0
White Balance Red: 0
White Balance Blue: 0
Picture Style: Standard
Digital Gain: 0
WBShift AB: 0
WBShift GM: 0
Color Space: sRGB
VRDOffset: 0
Sensor Width: 3944 (40-3927 used)
Sensor Height: 2622 (23-2614 used)
Black Mask Left Border: 0
Black Mask Top Border: 0
Black Mask Right Border: 0
Black Mask Bottom Border: 0
White Balance RGGB Levels: 2072 1024 1024 1570
Color Temperature: 4798
WB_ RGGBLevels Measured: 2003 1028 1019 1624
Color Temp Measured: 4575
Exposure Level Increments: 1/3 Stop
ISOSpeed Increments: 1/3-stop
ISOExpansion: Off
AEBAuto Cancel: On
AEBSequence: 0,-,+
Safety Shift: Disable
Flash Sync Speed Av: Auto
Long Exposure Noise Reduction: Off
High ISONoise Reduction: Off
Highlight Tone Priority: Disable
Lens Drive No AF: Focus search on
Lens AFStop Button: AF stop
AFPoint Selection Method: Normal
Superimposed Display: On
AFAssist Beam: Emits
AFDuring Live View: Disable
Mirror Lockup: Disable
Shutter Button AFOn Button: Metering + AF start
AFOn AELock Button Switch: Disable
Set Button When Shooting: Normal (disabled)
Dial Direction Tv Av: Normal
Focusing Screen: Ef-A
Add Original Decision Data: Off
Live View Exposure Simulation: Disable (LCD auto adjust)
Add Aspect Ratio Info: Off
GPSVersion ID: 2.2.0.0
Compression: JPEG (old-style)

[RoyL]

Originally Posted by kencaleno

Detach lens, adjust dioptre (next to viewfinder) so central focus point is sharply in focus. ( Never mind anything else, the focus point in viewfinder must be sharp) Preferably against a white background. Re-attach lens.

regards, Ken

I never thought of that. I always check mine with a 50mm attached because my other camera's do not have detachable lenses. I must try without the lens and see how much sharper I can get, not that I have an issue.

The Canon manual tells you to adjust until the center circle is sharp.

Thanks for helping me spell dioptre

[vandergus]

The shutter speed, 1/250, is on the edge of hand holdability (?) at 300mm. The blur you see could be from camera shake. Were you using a tripod?

[inkista]

Yeah, up your iso to 400 or 800, get a shutter speed faster than 1/300s (the rule of thumb for eliminating camera shake blur when handholding is to shoot 1/focal_length or faster), and stop down to at least f/8. No lens is at its sharpest wide open, and consumer zooms in particular tend to be soft wide open at the zoom range extremes.

Also, why manual focus if your eyesight is problematic? Why not use the autofocus system? Given today's viewfinders, the AF system might actually be more accurate than your eye in most circumstances. I'd actually advocate learning how to use the AF system. Selecting only the middle AF point so that you can select what your AF target is is a great technique.

[idcrewdawg]

Thanks for the advice! I've tried using the AF with the current lens (need to save for a better one), and the lens rarely focuses on exactly what I'm looking to focus on.

I didn't use a tripod, so that could be part of my problem. I've had difficulty positioning the tripod to meet what I'm looking for in shot composure.

On a related note, has anyone used the shoulder mounts that are available?