D 70 Re-calibration - How to do focus testing?

[rajesh_krishnamohan]

Hi all,

 

I wanted to find out if my camera has to be recalibrated as I suspect

that the images are not sharp enough. I am an amateur photographer

and I need some expert's opinion on how to do a "focus test" to

confim if I do need to send the camera for re-calibration.

Alternatively, I am also posting an image with this question and you

can help me.

 

Thank you in advance and Regards<div></div>

[Prof-K]

Where did you focused in this image?

[jim_gifford]

Set the lens focus at a specific distance, and place a target at that distance from the film plane. Shoot. Examine the result.

 

You could use all sorts of items for targets, but in general you want something that allows you to see the frontal out of focus area transition into focus, through the plane of sharpest focus, and then off into the rear out of focus area. The plane of sharpest focus should coincide with the set focus distance.

 

Measuring tapes and other regularly graduated targets work well.

 

Have fun,

[Prof-K]

Remember those photos that they showed you when explaining DOF? I'm talking about photos like: <a href="http://www.shortcourses.com/using/sharphess/phoneboothand_legs.jpg">this</a>

Try to take a photo like this with simple objects using a very fast lens (like the 85mm f/1.4). Carefully focus the center object. Then examine the result. If the center object is the sharpest one, then I guess there's no problem with your camera. Hope this helps.

[rajesh_krishnamohan]

Thank you for your replies.

 

The focus was somewhere on the horse. But given that the F-stop for the picture is pretty much on the higher side, I expected that the horse would appear very sharp. Am I wrong?

 

I should probably rephrase my question. Why is the image on the focus not very sharp?

 

 

Regards

[rich_dutchman1]

For an image straight from the camera, this is nice and sharp. You can increase the sharpness in your camera's settings - refer to the manual. Personally, I turn the sharpening off since the camera's sharpening algorithms can increase noise, and I sharpen in Photoshop.

 

If you are not making huge prints and shoot at low ISOs, then you can increase the in camera sharpening without much fear.

 

Try printing a few images, too. Images tend to look less sharp on screen.

 

One more thing -- sharpness is a subjective quality, and people see things differently. When I shoot a portrait, my in camera sharpening is off, I sharpen lightly in PS, then I add a second amount of sharpening only to the eyes. This makes a huge difference - really makes the image pop.

[an grianghrafadóir]

Focus in this image looks to be pretty even all over, you just need to sharpen it up. Raw files straight out of the camera are very soft. Open the RAW file in Nikon Editor (I prefer it over Photoshop's RAW Plugin) and use the Sharpening Tool. While you're there you can adjust contrast and colour balance too.