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by Bart Arondson

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2
votes
0answers
69 views

Help with calculating resolving power [closed]

I have liked your responses to the MTF questions and wondered if you could help me clear up an issue I have encountered. I have a Canon 7D with an assortment of EF and EF-S lenses. The current issue ...
5
votes
3answers
512 views

For MTF, why does 10 represent contrast while 30 represent resolution?

I'm trying to learn to read MTF charts. Everything is making sense to me, except why most explanations of MTF will refer to the 10 l/mm line as a measure of contrast while referring to the 30 l/mm ...
0
votes
1answer
767 views

How can I compare MTF50 to a manufacturer's MTF chart?

Currently working with a trial-copy of QuickMTF (Imatest's software kept crashing on me), and I'm trying to get some basic MTF readings for my Canon 85 f/1.8 lens on a 6D. My first set of test shots ...
1
vote
1answer
255 views

How to understand the picture height?

"The Spatial Frequency Response (MTF), shown to twice the Nyquise frequency. The key result is MTF50, the 50% MTF frequency, which corresponds to perceived image sharpness. It is given in cycles per ...
1
vote
1answer
247 views

Can a lens's bokeh be predicted by reading an MTF chart?

I've heard people say that everything meaningful about a lens's optical performance can be determined simply by looking at the MTF charts — although nothing is mentioned of that under How do I ...
5
votes
5answers
9k views

What are my options for an FX wide-angle prime to suit the D800's successor? [closed]

I have a D700 which I'm not planning to replace at this point in Nikon's product cycle. I'll porbably buy the D800's successor. Not because I don't like the D800 (especially its usability ...
2
votes
3answers
585 views

How can I compare the MTF results on Photozone from the Pentax SMC DA* 300mm with similar lenses from Canon and Nikon?

I have been researching the Pentax SMC DA* 300mm f/4 ED [IF] SDM as a possible wildlife lens to use with my K-5. There are only a limited number of reviews of the lens from reputable sources and even ...
6
votes
1answer
463 views

What does “distortion <XX%” mean in lens specs?

I'm going to buy a lens and I would like to understand what "distortion <XX%" means. It's a vari-focal 10-60mm lens, and mentions distortion <12-1%. According to my understanding, at 10mm focal ...
2
votes
1answer
332 views

Is the BxU measure of lens resolution still used by anyone?

The background In 2004 DxO released DxO Analyzer. It pioneered a new measure of lens resolution that it called BxU or Blur Experience Unit. Luminous Landscape reported on it (DxO Explained) and ...
33
votes
2answers
2k views

How do I interpret an MTF Chart?

As part of how Canon (and other lens makers) give technical information about their lenses, they supply an MTF (Modulation Transfer Function) chart. How do I read and interpret what the chart is ...