[zestoi]

just to add... my FA*55 is sharper than expected wide open at 1.4. my FA*85 isn't as sharp at 1.4 but doesn't need to be. has a great look for portraits, except for when it totally couldn't lock focus on my k1 recently a few times...

[alamo5000]

Be mindful of distance to subject as well. A lot of people frame up a subject that is six feet away not knowing that according to an online DOF calculator that's only just around 1 and 1/2 inches in focus at that distance and aperture.

[UncleVanya]

Wide open...

[mikeSF]

FA77 rendering is lovely wide open, but certainly not as sharp as it is by f/4.
I don't know any lenses that look their best wide open wrt ultimate sharpness. It's a tradeoff.

[Belgarchi]

What I did was pretty solid - Brick wall at 60 ft, manual focus with loupe, two series of photos at 1.8-2.8-4.0-5.6, 200 ISO, no anti-aliasing filter, anti-shake on, high shutter speed...
But the lack of contrast is incredible, it doesn't fit with what I read here, nor my past experience...
I wonder if it could be..... condensation inside the lens, it is very hot and humid here in Houston.
Will test again and let you know.

[clackers]

anti-shake on, high shutter speed...
But the lack of contrast is incredible, it doesn't fit with what I read here, nor my past experience...
I wonder if it could be..... condensation inside the lens, it is very hot and humid here in Houston.
Will test again and let you know.

On a tripod you want the anti-shake off, Belgarchi, if that's of any assistance.

[Belgarchi]

No need of a tripod at 1/3000th sec... and the image at f/5.6 and 1/250th sec is a lot sharper...

[stevebrot]

I wonder if it could be..... condensation inside the lens, it is very hot and humid here in Houston.

Fungus inside of lens? It may be time to give your FA 77 a good looking-through with a flashlight and loupe.


Steve

[Belgarchi]

My 77/1.8 is foggy inside.....
Any suggestion? I suppose I must go to the repair shop?

[slip]

I own the Pentax 77/1.8 FA-L for a long time.....
With my Pentax K10D (10 MP), and later my K30 (16 MP), I thought that it was an outstanding lens...
A few weeks ago I received the K70 (24 MP) and tested many lenses on a brick wall 60' away... very careful manual focus... and surprise, the 77/1.8 came off pretty bad.
It begins to be good at f/4.0, and is really good at f/5.6.
I think that it reached its limits with the 24 MP sensor even if it looks more like a contrast problem than a resolution problem.
Also, I wonder if there would be some sort of bad synergy between the 77/1.8 and the 24 MP sensor?

remember more MP allows the 100% zoom to be much closer.. so what looks sharp on let's say 16MP might be slightly blurred at 24MP. hope this makes sense

Randy

[Belgarchi]

Steve, thanks for the suggestion, you were right... My beloved lens is foggy inside (as well as my 20/2.8 FA ; and of course all my cheaper lenses are fine)
I hope it is not fungus, no 'linear' features, it looks like vapor... any suggestions before I go to the repair shop? Haidryer? Dehumidifier? Sun bath?
I am not able to open the lens, I am affraid I will not be able to assemble it perfectly after cleaning.

---------- Post added 08-26-16 at 12:19 PM ----------

I wondered why it is ok at f/5.6? Well, the 'fog' is on the periphery, the central area is clean.

[stevebrot]

My 77/1.8 is foggy inside.....
Any suggestion? I suppose I must go to the repair shop?

Oh! No!

In some ways it is good that you noticed so that you can get it fixed. OTOH, it sucks that it needs fixing.

Eric Hendrickson is the go-to guy around these parts for Pentax repairs. He does both film body and lens repair and his services are quite reasonably priced.

Eric Hendrickson: pentaxs.com


Steve

[Belgarchi]

Thanks but I know a wonderful camera repair shop here in Houston, on Richmond avenue.

[wibbly]

i wouldn't call the 77 overly soft wide open...



100% crop

[everydaylife]

Steve, thanks for the suggestion, you were right... My beloved lens is foggy inside (as well as my 20/2.8 FA ; and of course all my cheaper lenses are fine)
I hope it is not fungus, no 'linear' features, it looks like vapor... any suggestions before I go to the repair shop? Haidryer? Dehumidifier? Sun bath?
I am not able to open the lens, I am affraid I will not be able to assemble it perfectly after cleaning.

---------- Post added 08-26-16 at 12:19 PM ----------

I wondered why it is ok at f/5.6? Well, the 'fog' is on the periphery, the central area is clean.

Before you take it to a repair shop you should try putting the lens in a sealed container with some packets of moisture absorbent silica gel desiccant. My fa50 fogged so I put it in a ziplock bag with some packets and left it for a couple of days and it worked like a charm. Try it. If it works it costs you next to nothing. If it is fungus then I suggest that you rethink your storage methods.

I live in a country with very humid conditions and learned the hard way that leaving lenses in draws or bags in a humid climate is asking for trouble. In my first year here 2 lenses that I didn't use turned green inside. Fortunately I did not keep those lenses with my others as they probably would have been infected with fungus also. My quick and easy solution was to buy a small dry cabinet and no problems since. If you do a search on this site or on the internet you will find lots of info about storing lenses.