Hard to believe - but 28mm f2.8 and 28mm f3.5 Nikon primes beaten by A7 kit lens

Started Mar 19, 2014 | Discussions thread
Mel Snyder
OP Mel Snyder Veteran Member • Posts: 4,088
Re: Hard to believe - but 28mm f2.8 and 28mm f3.5 Nikon primes beaten by A7 kit lens

Mel Snyder wrote:

Tim Devine wrote:

My bet is that adapter registration distance is off.

Mel Snyder wrote:

When I had difficulty focusing my 35mm Summilux closer than 3 feet this morning, I decided to try two Nikon MF primes - a 28mm f2.8 Ai and a 28mm f3.5 Ai - both inherited from my late father, an photographer for Bethlehem Steel. Both focus very close - and a few years back, I'd shot the f2.8 on a Nikon FM, and it worked really well.

But when I tested both today on my A7, both were soft on the sides and corners - even at f5.6 and 8. They were very distortion free.But useless for landscapes

And so, for comparison, I shot the same scene with my kit zoom at 28mm f3.5. No comparison - the kit was sharp side to side, a tiny bit of corner softness. Even with LR 5.3, there was a quite a bit of vertical distortion beyond the lens correction profile. But the kit was sharper, more contrasty, more colorful. And a simple slider fixed it.

Anyone interested I can upload examples. But the first time some revered old primes tested so badly compared to a lowly kit zoom.

Could be - but it is perfect on my 85mm f2 Nikkor AiS and my 17mm f3.5 Tokina AT-X Pro, both wide open to exaggerate potential issues - that would cover registration issues with the lens with the smallest and longest helical travel close to infinity.

That's the only way I could think of a registration issue - one side should be out more than the other if the adapter wasn't straight in one plane or another - right? How else might I test it

I agree it is weird that both would be soft on the sides and sharp in the center. The 28mm f2.8 AiS gets a 100 score from http://www.photozone.de/active/survey/querylens.jsp so I assumed it would be great. But that score was on an APS-C camera, which doesn't see the edges.

I am more than ready to purchase a new adapter, if it's an adapter issue.

OOC image of the 85mm f2 at f2 - tree limbs sharp across frame

OOC image of the 28mm f2.8 at f2.8 - note the branches of tree at far left, evergreen at far right - worse on left = decentering?

Tokina 17mm f3.5 @ f4 - DOF here might cover ills, but so should long shot of 28mm above

Do you see anything? (other than I didn't notice the window frame at the top!) 

Kit lens before tilt correction - sharp across frame

Tilt corrected in LR5.3

 Mel Snyder's gear list:Mel Snyder's gear list
Sony Alpha NEX-6 Sony Alpha a7 Sony E 16mm F2.8 Pancake Leica Summicron-M 50mm f/2 Sony E 55-210mm F4.5-6.3 OSS +12 more
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