More on the Olympus 50-200mm f/2.8-3.5 SWD 4.3 lens

Turtles Sunning in Pond, Yorktown Battlefield National Park, Virginia (click to enlarge)
1/200th sec. @ f/5.6; ISO 200 with the Olympus 50-200mm f/2.8-3.5 lens
The original file was 16mp and this is a 2.7mp crop.  This image uses only 17.4% of the image area of the original.
This is a good example of the sharpness and accutance of this lens.

On Wednesday, I posted an image from my first outing with my Olympus 50-200mm f/2.8-3.5 SWD lens. Today, I wanted to expand upon what I previously wrote and show you some additional images that I made with this lens.

Each of these was handheld using the E-M1's in body image stablization (IBIS).  Again and again, this feature has proved itself as one of the best reasons for buying an E-M5 or E-M1.  Although the lens has a robust and removable foot to which you can mount it to a tripod, I have not yet used it in the field.

The Olympus E-M1, with a native M4/3 lens, will use 81 contrast detecting focusing points.  Native M4/3 lenses focus very fast and very, very accurately.  But, when you attach a lens designed for the original 4/3 format, the camera automatically switches over to use 37 phase detecting autofocusing points embedded in the imaging sensor itself.  It still focuses fast and accurately, though not quite as fast as with the lenses that were natively designed to be used by this camera.

Yorktown Battlefield National Park, Virginia (click to enlarge)

By the nature of how it works, phase detection auto focus (PDAF) is faster than contrast detection autofocus (CDAF).  If you don't believe me, try your best M4/3 camera and best M4/3 lens against a Nikon D4S with one of its best lenses. See which one is faster every time.

Briefly, PDAF will know which way the lens needs to be turned and by how much.  It will go to that point very quickly.  CDAF has to start lens movement in order to understand if the scene gets more contrasty (closer to correct focus) or less contrasty (farther from correct focus) and then turn the lens in the direction of greater contrast. Once it hits maximum contrast (image in correct focus), the lens will go slightly past that point and see that contrast is now being reduced, back itself up and stop on maximum contrast.  At least this is how I understand it.  This takes place almost instantly so this system is no slouch, but PDAF is technically capable of faster results.  The downside with PDAF is that it is not as accurate as CDAF as CDAF focuses directly off the front of the sensor using live view while, typically with digital SLRs, PDAF goes through a separate module to achieve focus.  That is why digital SLR makers include a mechanism to "micro adjust" the cameras to individual lenses to take into account any mismatches between cameras and lenses.  I'm not sure how this system differs with mirrorless cameras.

The mirrorless camera manufacturers are now putting phase detect autofocus sensors on the imaging chips of the newest M4/3 cameras which enable them to use the original 4/3 lenses successfully.  I suspect, with additional time, that you will see more and better phase detect sensors being placed on the image sensors of the next generation of M4/3 cameras.  However, that does not mean that the original 4/3 format lenses don't work well on today's cameras as they do.  So far, I am pleased with the Olympus 50-200 f/2.8-3.5 SWD lens on my Olympus E-M1 camera.

My next set of tests with this lens will be on moving objects.  I plan to go out over this holiday (Labor Day in the United States) weekend and try this lens with objects moving across the frame as well as toward the frame.

Why am I doing all this?  To learn and understand my gear.  If you don't fully understand your gear, you won't be able to fully take advantage of its strengths and, equally, won't be able to understand its weaknesses so you can avoid them or at least minimize their impact on your photography.  The upshot is to fully leverage whatever gear you have to make the best images you can under all circumstances you may encounter.

Farm along the Colonial Parkway between Jamestown and Williamsburg, Virginia (click to enlarge)

Thanks for looking.  Enjoy!

Dennis Mook

Many of my images can be found at www.dennismook.com.  Please pay it a visit.  I add new images regularly.  Thank you.


All content on this blog is © 2014 Dennis A. Mook.  All Rights Reserved.  Feel free to point to this blog from your website with full attribution.  Permission may be granted for commercial use.  Please contact Mr. Mook to discuss permission to reproduce the blog posts and/or image.