This doesn't proof anything conclusively, but now I know that I should carefully research the matter before I buy... And this is what the sensible photography equipment manufacturers are doing. They don't go by the numbers, charts etc. They go by the final result. Olympus PEN-F + Olympus M.Zuiko 40-150mm f/4.0-5.6 R (145mm, 1/400 sec, f/5.6, ISO200) (Image credit: James Artaius) Olympus M.Zuiko 40-150mm f/4.0-5.6 R: Performance Finally at 150mm, sharpness levels drop a little across the frame at maximum aperture, but remain very good in the centre whilst approaching good levels towards the edges. There is little difference in edges sharpness with the lens stopped down, although sharpness in the centre does reach excellent levels at f/8 at this focal length. Requirement to increase the ISO is as well one thing that makes sharper lenses benefit negligent. But in situation like ISO 200 vs ISO 800 there can be a benefit. So f/4 is the difference maker over f/6.3 that is just 1.3 stops slower (ISO 200 vs 500) and it can be very tiny even in many cases (unlike example ISO 3200 vs 8000).

Panasonic 50-200mm F2.8-F4 v Olympus 40-150mm f2.8 - Mu-43 Panasonic 50-200mm F2.8-F4 v Olympus 40-150mm f2.8 - Mu-43

The new Lowara ecocirc XL and XLplus are the wet rotor circulators that provide state-of-the-art technology in hydraulics, motors and intelligent controls. The ecocirc XL and XLplus are everything you need in a large wet rotor circulator and nothing you don’t. The purposefully engineered, easy-to-install ecocirc XL and XLplus are designed with simplicity and efficiency in mind. As on the M.Zuiko 12-40mm f2.8 Pro, the focus ring can be used in one of two modes. A manual focus clutch mechanism is engaged by snapping the focus ring rearward, which also reveals a focus scale marked on the lens barrel. In this mode the lens is focused mechanically with physical stops at either end of the range. In the forward position the scale is obscured, you can still manually focus, as long as the camera is in MF mode, but turning the ring focuses by wire using the AF motors. Focusing on the M.Zuiko 40-150mm R was blazingly fast, and that was an impressive feat considering the lens is covering long focal lengths reaching up to 300mm equivalent. The great thing about focusing with OM-D/PEN bodies is the dead-on accuracy, I rarely find miss-focused shots, if there were any, those were probably my own fault (setting the focusing point at the wrong place, or not being fast enough to react to the subject). The focusing does slow down a little in dark shooting conditions, but still averagely fast enough without causing much impact in getting the shots done. When it gets it right the 40-150mm f2.8 produces stunningly sharp detail. This time set to S-AF mode with the light fading, but still bright enough to shoot wide open at 200 ISO with the stabilisation enabled.I've had a bit more play-time with my new MC-20. It was a brighter day and I got a few more acceptable test shots. That said, the keeper ratio was still lower than I expected and I think there will be a learning curve to get more out of it. It's still early days, though I have a feeling it was easier to get sharp shots out of my P100-300 when the AF played ball. Maybe that is down to OIS vs IBIS at 300mm? Of course, it might just be that I've forgotten how many poor 100-300 shots I deleted.

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A fast, accurate AF with high close-up performance, achieved with the world's first Dual VCM focusing system*4 When I only had the 75-300 I primarily used the small single focus square. When applying the same technique in darker conditions with the 40-150, I think it may hunt and miss more than with the 75-300. I think this is because the wide open depth of field available to the AF mechanism is smaller for the 40-150. When the birds are not well lit the AF has less to work with. It always focuses wide open, so stopping down doesn't help. Perhaps I need to work differently when the light is really bad or the DOF really shallow. The E-M1's focus limiter seems like it would be very useful for my circumstances. Before I move on to talk about the optics and focusing, just to note that like several other lenses in the Olympus range the 40-150mm f2.8 Pro has a L-fn function button on the barrel that can be assigned to one of a number of functions from the custom menu on the camera. Olympus 40-150mm f2.8 Pro optics When fitted to the OMD EM1, the camera and lens combination is beautifully balanced. It feels just right, not just when carrying it around but when you raise the camera to your eye and shift your left hand from the tripod mount to the zoom ring. Finally, there is the MC-14 1.4x teleconverter, the first developed for MFT lenses. It is relatively flat (14.7mm) so using it won’t affect the size of your system. It features a very similar build quality to the lens with an all-metal finish. The front lens protrudes from the converter, a design that will limit its compatibility to the Olympus 40-150mm and upcoming 300mm f/4. It won’t work with other MFT telephoto lenses.Optically the Olympus 75-300mm does very well, but not where you'd want it to - it's super-sharp at 70mm, not at the 300mm where I suspect the grand majority of users will want to use this lens. At 300mm, it's only above average, there's noticeable chromatic aberration, and the maximum aperture of ƒ/6.7 is one of the slowest I've seen for SLR lenses" Doing a common 8x10" prints and it renders lenses like 300mm f/4 moot by sharpness compared to 75-300mm @ 300mm as you are wasting resolution benefit in small print. The M.Zuiko 40-150mm f2.8 Pro is environmentally sealed with 11 separate seals to keep out dust and moisture making it splash-proof and dust-proof as well as freeze-proof. I used the 40-150mm on the Olympus OMD EM1 – a weather-sealed combination – during steady drizzle without complaint from either. Following an initial day of testing at the Cheltenham horse races with Ken McMahon, Gordon sourced a second sample of the lens and tested it for a month in a wide variety of portrait, landscape and action environments. He also retested the lens with the Olympus ODM EM1 updated to firmware 2.2 which claims to deliver superior AF precision with the 40-150mm. Read on to find out if this is the telephoto zoom Micro Four Thirds owners have been waiting for. Olympus 40-150mm f2.8 Pro design and build quality

40-150mm crop: Micro Four Thirds Which is better? 75-300mm or 40-150mm crop: Micro Four Thirds

Inside the 40-150mm f2.8 Pro there are 16 elements in 10 groups including ED, Super ED, EDA and HD elements. Essentially these technologies are designed to reduce internal light dispersion (ED stands for Extra-low dispersion, EDA is Extra-low Dispersion Aspheric and HD is High refractive index & Dispersion) and improve image quality and contrast. The minimum focus distance of 0.9m is quite close for a lens with an angle of view equivalent to a 300mm lens - ISO200, 1/250, f/5.6, 150mm (35mm equiv – 300mm) Olympus PEN-F + Olympus M.Zuiko 40-150mm f/4.0-5.6 R (45mm, 1/125 sec, f/4.1, ISO200) (Image credit: James Artaius) Olympus M.Zuiko 40-150mm f/4.0-5.6 R: Key featuresShooting wide open at 40mm, sharpness in the centre of the frame is excellent, and the clarity towards the edges of the frame is fair. Stopping down the lens improves sharpness towards the edges, with the best compromise for sharpness across the frame being achieved between f/5.6 and f/8, where the centre is still excellent, and the clarity towards the edges reaches good levels. Within the Micro Four Thirds range, the closest rival is Panasonic’s 35-100mm f2.8 which measures 67mm in diameter 100mm in length and weighs 360g, significantly smaller and around half the weight of the Olympus. That difference is all the more remarkable when you consider the Panasonic lens is optically stabilised where the M.Zuiko 40-150mm relies on the built-in stabilisation of Olympus OMD and PEN bodies to iron-out any wobbles. That said, there is of course also a substantial difference in the respective zoom ranges of these two with the Panasonic lens’s ‘classic’ 70-200mm equivalent range starting slightly wider but stopping well short of the 80-300mm equivalent range of the Olympus lens. The constant f2.8 aperture is maintained throughout the focal range, a very useful feature and not just for shooting in low light. The physical aperture diaphragm construction is composed of 9 blades which produce a circular shaped aperture that should result in pretty circular blob highlights for out of focus elements. At the other end of the range the minimum aperture is f22. The 40-150mm f2.8 has a closest focus distance of 70cm. That’s constant regardless of the focal length so you can get close in at 150mm to produce very shallow depth of field shots. The only thing to mention is that the 40-150mm makes your kit less discreet. From a distance, it doesn’t look much different from a D7100 with a 70-200mm f/4, especially from the perspective of a non-photographer. But you get less weight and more reach, so there is a benefit if we want to compare it to a medium-sized DSLR kit. I actually wrote a specific article about this topic recently which you can read here.

Olympus MC-20 converter with 40-150mm f2.8 zoom | Mu-43 Olympus MC-20 converter with 40-150mm f2.8 zoom | Mu-43

Bokeh is a word used for the out-of-focus areas of a photograph, and is usually described in qualitative terms, such as smooth / creamy / harsh etc. In the M.ZUIKO Digital 40-150mm f/4-5.6 ED, Olympus employed an iris diaphragm with 7 rounded blades, which has resulted in a pretty decent bokeh for a zoom lens, at least in our opinion. However, recognising that bokeh evaluation is subjective, we have provided a few examples for your perusal. IMO the 40-150mm cropped would still have a better quality image then the 75-300mm at full focal length. If any of this sounds important to you, the Olympus 40-150mm F2.8 Pro is one of my all-time favorite lenses and an easy recommendation. Read Olympus 40-150mm F2.8 Pro Review for more information. Of course, time will tell. But based on the Olympus 40-150mm’s F4’s MTF, it appears to be an excellent performer with excellent sharpness across the entire frame. If their customer audience is 80% of people that are doing 98% of the time prints size of 16x11" and 2% just little bigger and otherwise photos are on Full HD or HD displays, that is the starting point where the comparison will be made as it is the output that rules everything.The lens weights about 760g without the tripod mount, which is heavier than the E-M1 or any other MFT camera. I decided to use it with the E-M1 without the HLD-7 battery grip, not only to keep the combo as small as possible but also to see how the extra weight and size would affect the usability of a system known to be more compact than this. After carrying it around every day for my daily work for two weeks, I can say that in the end that the weight and size don’t make a huge difference, as the lens still fits nicely inside my primary camera bag, the Lowerpro Event Messenger 150. Yes, the lens is big but still compact enough for the zoom range it covers.