A mini story about a mini-wide...

[Zang]

A couple of years ago, I found an online ad from a gentleman who wanted to give away a vintage film camera. I was lucky enough to be the winner who picked the camera up. It turned out that the camera was owned by the man's late father who died in 1988. He kept his dad's camera for many years before decided it needs a new home. The camera was brand new and based on the model's name, it was released to the market in 1985. That means the father did not have a chance to enjoy it for too long. On another hand, the lens - Sigma Mini-Wide 28mm f2.8 - was old and was not functioning well. I put the camera in my office as an display item and it had been there for the last few years. Today, I decided to take the lens apart for cleaning, hopping to bring it back to its wonderful life. After a couple of hours, the lens is back in one piece, fresh, clean and functioning smoothly like it just left the production line yesterday. It turned out to be a wonderful performer. The papers are my notes on how to reassemble the lens back.

[Hugh_3170]

"He who dares wins" is an apt quote for your well executed success.  Kudos Zang.

A couple of years ago, I found an online ad from a gentleman who wanted to give away a vintage film camera. I was lucky enough to be the winner who picked the camera up. It turned out that the camera was owned by the man's late father who died in 1988. He kept his dad's camera for many years before decided it needs a new home. The camera was brand new and based on the model's name, it was released to the market in 1985. That means the father did not have a chance to enjoy it for too long. On another hand, the lens - Sigma Mini-Wide 28mm f2.8 - was old and was not functioning well. I put the camera in my office as an display item and it had been there for the last few years. Today, I decided to take the lens apart for cleaning, hopping to bring it back to its wonderful life. After a couple of hours, the lens is back in one piece, fresh, clean and functioning smoothly like it just left the production line yesterday. It turned out to be a wonderful performer. The papers are my notes on how to reassemble the lens back.

[Zang]

Thanks Hugh Have a nice weekend!

[Hugh_3170]

You too.  May your team win.

[Zang]

You too.  May your team win.

Thanks Hugh!

My quick test (on APSC) showed Mini Wide outperforming Nikkor AIS 28/2.8 at longer distances at 5.6 and wider. Close up, Nikkor edges Mini Wide a bit but it is hardly noticeable. Quite surprising to me!

[Fons Baerken]

Great project, show some results please Zang!

[Zang]

Thanks Fons!

I have taken some close-up test only, nothing 'photographic'. At close distances, the lens is pretty good. Not quite as sharp at infinity, but the CA is very well controlled. The first picture bellow was taken at 2.8 in low light condition using Sony Nex 6. The second picture was taken at 5.6 (Note that both files have aggressive compression to fits NG requirements).

[Zang]

And the lens itself, on NEX-6

[Zang]

Again, 2.8 and 5.6.

[Zang]

Comparing with Nikon 2.8 AIS at 2.8 and near infinity (center crops). Nikon is the worse one.

[Zang]

Portrait at 2.8 and 5.6. 100% crop look both very sharp.

[MEPER]

Comparing with Nikon 2.8 AIS at 2.8 and near infinity. Nikon is the worst one.

I assume that last one is the "Nikkor"?

The first one looks like DOF is much larger. Sharp at infinity but also a bit sharp at close distance?
The Nikkor looks more like a "toy-lens" not like a Nikkor?    .....not sharp anywhere?

[Zang]

I assume that last one is the "Nikkor"?

The first one looks like DOF is much larger. Sharp at infinity but also a bit sharp at close distance?
The Nikkor looks more like a "toy-lens" not like a Nikkor?    .....not sharp anywhere?

Yes, the later one was from Nikkor. Stopped down, Nikkor is doing OK. Close up Nikkor wins by edges. I hope it's sample variation, but sample variation is also a quality indication of a brand.

[Zang]

I notice the photo from Nikkor was overexposed a bit due to auto-ISO out of range. I corrected the exposure and both the sharpness and CA at 2.8 were improved a lot. I did not know exposure can affect sharpness and contrast. However, the level of CA still remains higher than the one from Sigma Mini Wide. I tested the whole bunch of my wide lenses including Nikkor 24mm f2.8, Nikkor 28mm f3.5, Contax Zeiss 28mm f2.8, Canon FD 24mm f2.8, Minolta MD 28mm f2.8 and Niikor 24mm f2.8 is the winner. Wide open, CA is absent. It is also the sharpest at infinity wide open. Nikkor 28mm f3.5 also does not suffer from CA wide open, but the sharpness falls off so quick toward the edges.

[Hugh_3170]

Do you have the opportunity to compare these two 28mm f/2.8 lenses on a camera with a larger sized FX/24x36mm (aka "Full Frame") sensor?

To some extent the small DX/APS-C sized sensors tend to be a great "leveller" in the sense that they only show us the the central area of an FX/24x36mm sensor (~the middle 50% of "full frame"), and the edge performance of the format that they were designed for is excluded when used with the smaller sensor.