Richard Turton

Joined on Dec 17, 2013

Richard Turton's recent activity

  • Lightroom always applies lens corrections to micro FT lenses because the correction data is included in the EXIF data.  For the original FT lenses you have to provide a lens profile because there ...
  • Replied in Teleconverters
    It is very difficult to find any solid information about how teleconverters affect image resolution. This article is the best I have been able to find, although it is a bit dated since it talks ...
  • Replied in Teleconverters
    If you already have a teleconverter it is worth doing a comparison of image quality with and without the TC, at the same lens aperture from the same camera position.  You should do a number of ...
  • Contrary to my expectations, this information has not proved to very useful other than helping to understand how the focus bracketing works.  It is simply not practical to determine distances and ...
  • Which approach is more likely to lead to increased sales for Adobe?  Speeding up the basic functions or adding gimmicky new features?
  • Replied in Correction
    I ran the video benchmark again and found that the 4K frame rate for the GTX 1050 is only 10-15 fps.  I should have known not to rely on my memory.
  • I am using a GTX 1050 2 GB in a Dell XPS8700 to drive two monitors, a 3840x2160 and a 2560x1440.  This setup is probably not fast enough for games or video editing but is completely adequate for ...
  • Thirty plus inkjet prints, 8x10 to 13x19, displayed in cheap frames.  The glass in the frames noticeably degrades the image quality.  Most of them have bad lighting and problems with reflections.  ...
  • The E-M1 is a much better camera than the original E-M5, with a lot more functionality although the image quality is more or less the same. The E-M1 originally had shutter shock problems with some ...
  • It is definitely an E-M1 Mark I.  As you correctly point out, I failed to correct for the fraction of the total frame height occupied by the waveform.  But the example shown has been cropped.  The ...
  • This photo of an oscilloscope trace was captured with an E-M1 using electronic shutter at 1/1000 sec.  The time base is 5 ms/div and the sensor scan time seems to be about 22 ms or 1/45 sec.  The ...
  • Here are the MTF50 (sharpness) curves for the 12-40 f/2.8 measured using MTF Mapper.  Like most 4/3's lenses it peaks at f/5.6 but is very good over the range f/4-f/8.  Diffraction takes over past ...
  • It is worthwhile to compare the image quality produced by a teleconverter to the alternative of simply resampling and upscaling the original image.  The teleconverter does not always produce ...
  • I can identify with that last sentence.  I have done a lot of measurements using MTF Mapper (because it's free) and find that the results are very sensitive to changes in test conditions, ...
  • Sorry for the lack of clarity.  I was trying to agree with the point, not often mentioned,  that there is a lot of shot to shot variation with Phase Detect autofocus, making focus adjustment a ...
  • This is the best posting on this topic I have seen.  I have found that there is a lot of variation in MTF measurements of the ZD 50-200 on the E-M1 when using PDAF and refocusing between frames.  ...
  • The main differences between the 14-42 and 40-150 kit lenses and the expensive PRO lenses are speed (maximum aperture) and quality of construction.  I have both of these kit lenses that came with ...
  • Replied in Follow up
    After posting this I started to think about why using a teleconverter produces approximately the same image quality as cropping and up scaling the to produce the same size final image. Eventually ...
  • I am starting to have doubts about the value of teleconverters. Unfortunately I don't have the 300 f/4, but I have recently done some tests with the older ZD50-200 zoom and the EC-14 ...
  • Replied in EM1 MK1 used
    Andrew, I would also like to have the superior focusing of the Mark II, but it is a lot of money and I don't really need the other new features.
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