Nikon D60 and Siggy 70-200 front focus

simonedgar

simonedgar

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Hi i belive i've got the a problem on my 70-200 f2.8, recently had the AF motor repaired and came back with my shots look OOF/ soft. Ive took a few test shot (as Per http://www.focustestchart.com/chart.html)

These are the results

3668707506_a64d52b6a4.jpg


iso 100 70mm f2.8 1/2500 auto WB

3667899409_73278a5329.jpg


iso100 200mm f2.8 1/2000

Both set on tripod @ 45deg angle, remote release

Am i right that this is badly front focussing???

Thanks
Simon
 
You'll get a bunch of people come along in a minute saying that the particular test chart is no good for that sort of test... (I'm not one of them)

So, firstly, do you have another (pref Nikon) lens that you can use as a test? I say Nikon, because if you have the same issue with a Nikon lens, you can send the pair in for adjustment - if you send the camera in with a Siggy on it, you can bet your life that Nikon will blame the lens.

Anyway - have a look at my threads before and after my focus issue I had on my D200 - the difference is remarkable. What I did to show the issue is line up books on a table, so there was a clear, flat plane to focus on, with the contrast in the text on the cover of the book used as a good focus point.

And, for information - I used the same test chart as you and it indicated that there was a back focus issue on my kit, so there are times when that chart can be used successfully....
 
Well it appears to have front focusing. Did you test it before you sent it, or are you just starting to test it now.

Whats is like shooting in more typical shooting situations?

Try shoot a target (say a chimney stack 100 yards away wide open @ 200).
 
Thanks Outlore and Puddleduck

I've tried it with my Kit lens and 55-200mm, finding small difference, but only v slight!

@Puddleduck shooting at that distance it seem "ok" I'm lacking some experience now...

3673168666_d7bd6c5269.jpg

Focus is point of roof in the centre house

Any other simple/easy test???


Thanks v much
Simon
 
simonedgar said:
Thanks Outlore and Puddleduck

I've tried it with my Kit lens and 55-200mm, finding small difference, but only v slight!

@Puddleduck shooting at that distance it seem "ok" I'm lacking some experience now...

3673168666_d7bd6c5269.jpg

Focus is point of roof in the centre house

Any other simple/easy test???


Thanks v much
Simon
Click to expand...

I think we'd need a 100% crop TBH
 
OK...well IMHO shooting test charts close to a lenses minumum focus distance is flawed and stands a good chance of finding problems that don't exist, which is why I suggested the chimney shot.

I really suggest you don't use that chart. Bin it.

Go outside tomorrow and just find some real test targets at various distances - in fact, just walking down your street, car number plates are great targets - they present good contrasty AF targets. Try a few at various distances, ie 5 yards, 20 yards etc etc. 80 yards.

I can't comment whether you have a problem... you might have.. but try shooting away from charts and see what you think.
 
puddleduck said:
OK...well IMHO shooting test charts close to a lenses minumum focus distance is flawed and stands a good chance of finding problems that don't exist, which is why I suggested the chimney shot.

I really suggest you don't use that chart. Bin it.

Go outside tomorrow and just find some real test targets at various distances - in fact, just walking down your street, car number plates are great targets - they present good contrasty AF targets. Try a few at various distances, ie 5 yards, 20 yards etc etc. 80 yards.

I can't comment whether you have a problem... you might have.. but try shooting away from charts and see what you think.
Click to expand...

The thing with the charts is most people only use one if they think they have a problem already... so the OP has already made a decision that there may be something wrong and therefore has used the chart - I agree that you could find problems if you look hard enough, but to dismiss any test as not a real target is a little silly, imho.

My suggestion is: if you feel unsure about it, get it back to Nikon for adjustment - you'll need to provide some evidence in pictures I would imagine...
 
OutLore said:
My suggestion is: if you feel unsure about it, get it back to Nikon for adjustment - you'll need to provide some evidence in pictures I would imagine...
Click to expand...

Yes. Good evidence.

Test targets need to be perpendicular to the AF system, not at an angle.

This is Canon's take (Chuck Westfall)

" Do not attempt to autofocus on an angled chart, because doing so will degrade the consistency of the camera's focusing measurement. Keep in mind that the camera's AF sensor is comprised of multiple pairs of linear pixel arrays. If you attempt to autofocus on a single line in an angled focusing chart, only a few pixels from each active pixel array will "see" the target. Ideally, the contrast in the reference target should cover the entire area of the camera's center focusing point, and the reference target should be perfectly parallel to the camera's focal plane."

Nikon adopt a similar position.

I advise using good testing which helps produce convincing evidence :)
 
I had the same thoughts about my lens, and i can definately say that those focus test charts are a waste of time and only make you think that you have a real problem with the lens.

Best thing to do is get outside and focus on different objects at different ranges, dont make the same mistake as me and use it at f2.8 and focus on something a couple of metres away cos the depth of field is very small.

Chances are your lens is probably fine, i worried for months and months about mine and all the problem was in fact was me not knowing enough about the depth of field! tut tut

And i use a Nikon D40x and Sigma 70-200mm 2.8 Macro II by the way.
 
Had another play this afternoon.... Maybe i just cant take photos.... I'm @ the Renault World Series this weekend i'll see how i get on!

3676301926_0d2c3ca6b1.jpg


Crop

3676302184_a204734f98.jpg


3675484167_5bd046aae8.jpg



Thanks very much for the advice

Simon
 
when taking pictures like that of the dog, try it in f6 and f8, i done some portraits of my girlfriend in f8 and they turned out mega sharp!
 
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