Struggling with D7100

Started 7 months ago | Questions thread
Westmill
Regular MemberPosts: 443Gear list
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Re: angles
In reply to Mako2011, 7 months ago

Mako2011 wrote:

Westmill wrote:

This is where I calibrate my own lenses....

This is one of a fair few I did when calibrating ... errrr I the 60mm I think

Again, because the array's have a horizontal and vertical component (worse in D7000 due to array size)...setting your AF-Fine tune based on angled targets (especial close range) can result in an inherent error. May not show up when you "check" using a flat wall and CDAF vs PDAF comparison due to DoF limitations. Will show up though (if the setting was off) when shooting at different distances at subject occupying a tiny field of focus.

Example: This is is a perfectly calibrated 50mm lens (requires zero adjustment). Focused here on the center dark line. Had I used these results to set AF-Fine tune...I would have induced an error and set a - correction when none was actually required.

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My opinions are my own and not those of DPR or its administration. They carry no 'special' value (except to me and Lacie of course)

Yes i understand that. But !  you are using a very flat and tiny line. The wire protrudes and is big enough to fill almost the whole sensor. Also getting too close is not a good idea either as even a tiny error at short range can swiftly evolve into very large errors at far off subjects. The simple fact is, that it works and works well. Yes of course you can go to any extreme and get even better results but you would be hard pushed to see them. This has worked for years for me with no problem whatsoever. It is hard to argue that a bullet in the head is not deadly when there are loads of corpses at your feet that says otherwise

This is a Problem with the Pentax K5 and why everyone thinks they have back and front focus issues. With the K5 it is caused through the focus sensors are the size of dinner plates. When you look through the viewfinder, the focus squares appear to be of normal size. The actual sensor expands well beyond the squares though. About 6 times the size actually. The sensor is so big that you can say, focus on an eye, which of course is very close to the side of the head, and the sensor is so big there is nothing to stop it focusing on perhaps the nose or ear, or even miss altogether and focus on the background. So of course, very few users know or understand this... hence most think they have front or back focus issues. The trick of course is not to be so selective. You do not focus on the eye, but just use the face

Very much the same thing here. As in most things you need to apply a degree of common sense. The important thing here to me is... if it works your far far better off and if it does not you have lost a couple of hours trying. I posted lots of info so anyone has a fighting chance. My money is on the vast majority would see a notable improvement.

 Westmill's gear list:Westmill's gear list
Nikon D700 Nikon D7100 Sigma 50-150mm F2.8 EX DC APO OS HSM Tamron SP 24-70mm F/2.8 Di VC USD Sigma 18-35mm F1.8 DC HSM +2 more
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