Sharpness test shots: MZD 75-300 II with and without UV filters

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NZ Scott
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Sharpness test shots: MZD 75-300 II with and without UV filters
4 months ago

Hello campers,

There have been a few threads recently in which a few old topic-chestnuts have reared their heads, resulting in the usual heated debates.

1) UV filters, with some detractors going so far as to say that the extra layer of glass "ruins" shots, while their proponents say that they see no appreciable loss in image quality.

2) The 75-300 II lens, with everybody agreeing that it's a bit softer at the long end, but with some quite vitriolic assertions about the degree to which this is so.

Furthermore, one person who uses the 75-300 II stated that he noticed an appreciable drop in sharpness when using a specific filter, the Hoya Pro1 Digital Multi-Coated UV, but no drop in sharpness with another brand.

Well, I happen to own the 75-300 II, a Hoya Pro1 Digital Multi-Coated UV, and another highly-regarded filter - the B+W 010 MRC UV with Nano coating.

So, it's Friday afternoon and I can't be bothered working on my novel but I've run out of ways to procrastinate. Why not do some test shots? Okay, lets.

I began the test thus: I mounted the 75-300 II on my E-P3, then mounted the camera on a tripod (Sirui 1204x carbon-fibre with Photo Clam PC33NS ballhead), extended only the first portion of the legs, retracted the centre-post and locked everything down hard. I set the camera to manual mode, ISO 200, f8, 1/20 sec, which produced 1/3-stop over-exposure in my living room, which has a constant source of natural light, and turned off the IBIS. I moved up close to my target, a papyrus painting that my missus bought in Cairo, auto-focused on the pharaoh's left hand using the smallest focus box, and I took the following test shot in Raw (later converted to jpeg using standard ACR settings and without being cropped) using 2-sec antishock:

I then take a series of shots at 75mm, consisting of the following:

1) "Naked" lens

2) B+W filter

3) Hoya filter

I rack out the lens to 300mm and move back so that the image is framed exactly the same as it was at 75mm - or, at least, as closely as possible - and take the following shots:

1) "Naked" lens

2) B+W filter

3) Hoya filter

CONCLUSIONS:

1) My 75-300 II is significantly sharper at 75mm than it is at 300mm, with fine details being smudged away at the longer focal length.

2) There is NO DIFFERENCE in image quality between any of the three filter/non-filter parameters. When really pixel-peeping at 400 per cent magnification, the B+W filter was very slightly SHARPER than the naked lens/Hoya at 300mm (judging by the tiny hair above the pharaoh's wrist and a couple of blemishes on the papyrus to the right of the pharaoh's upper arm)

The first result was not a surprise to me, as under real-world shooting conditions I have found the 75-300 II to be consistently very sharp out to 220mm (occasionally matching my 60/2.8 Macro at closer distances), occasionally ver sharp at 250mm, and a little soft at 300mm.

The second result was a surprise. I had been expecting the Hoya to produce slightly softer images, but it did not. I had been a bit worried that some soft-ish images I had taken in Africa at 300mm were possibly affected by my use of the Hoya, but I am now confident that it was more likely the shooting conditions and the lens itself.

Neither filter has EVER flared on me while using the 75-300 II.

I'll post 100 per cent crops (from near the centre) below.

Right, there's one hour of my life gone - what to do with the rest of the afternoon?

First, at 75mm:

Second set, at 300mm:

Questions and comments welcome, of course.

S

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My Flickr stream:
http://www.flickr.com/photos/scottkmacleod/
My kit: E-P3, 12/2.0, 17/1.8, 45/1.8, 60/2.8 Macro, 7.5 Fisheye, 12-35 f2.8, 14-42 IIR, 40-150 ED, 75-300 II

 NZ Scott's gear list:NZ Scott's gear list
Olympus PEN E-P3 Nikon AF-S DX Nikkor 18-55mm f/3.5-5.6G II Panasonic Lumix G Vario 7-14mm F4 ASPH Olympus M.Zuiko Digital ED 40-150mm 1:4-5.6 Olympus M.Zuiko Digital 14-42mm 1:3.5-5.6 II R +9 more
Olympus M.Zuiko ED 75-300mm 1:4.8-6.7 II Olympus PEN E-P3
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