Corner sharpness on FX sensors versus film

I am reading a lot of posts about the concerns of corner sharpness on FX sensors.

I have shot film for 20 years so just thought if I went from my DX camera to an FX camera my corner sharpness would be the same as the old film days??

I had heard a brief comment that sensors can't cope with this issue like film did.

If this is true, can anyone explain this?

Thanks

Mary

I had heard a brief comment that sensors can't cope with this issue like film did.

True

If this is true, can anyone explain this?

Not without a lot of thinking and typing. Here's is the abbreviated version from the summary of the Cliff's Notes:

Film is flat. Light gets directed to the flat surface. Photosites are like wells. Light coming from the edges don't hit the bottom of the wells very well.

Someone will be along shortly to explain it in better detail if required.

Film is actually curved George - which also helps.

Cheers

James

Not all cameras curved the film, but many of the best ones did. It's a lot easier (and cheaper) to make a curved plate that bends film than it is to make a curved computer chip.

As for the wells, the Leica M8 actually has some micro-lenses embossed onto a thin filter plate that refract the light and direct it in the proper direction down the wells. Although this should be a cheap design to mass-produce, I haven't seen it used anywhere but on the high-end Leica yet.

All digital sensors use a filter pack w/ microlenses over the sensor.

Cheers

James

All digital sensors use a filter pack w/ microlenses over the sensor.

 

Cheers

James

Sorry, should have said "offset microlenses".

AFAIK, most digital sensors use the same microlens-to-photosensor alignment on every pixel, while Leica changes the alignment on pixels depending on the distance from the center of the frame to the pixel, in order to combat vignetting. There's a much clearer explanation in this review

review

Likely off top-topic, I apologize, but regarding M8 and to turn things slighly upside down, the following review:

"there are dozens and dozens of amazingly sharp and small manual focus lenses available for very reasonable prices that work wonderfully on the Micro 4/3 cameras right now. Already the ‘alternative lens forums’ like the one at FredMiranda.com are filling up with reports by the more experimental hobbyists about using lenses like the Voigtlander 15mm and older Leica rangefinder lenses on Micro 4/3s cameras....

This is the main reason I think Micro 4/3s will be a smashing success even before the cameras are what we hope they’ll be. Its the perfect platform for the hobbyists and experimenters among us to play with rare and classic glass. I’ve already heard the E-P1 called the ‘poor man’s Leica M8 rangefinder’ for just this reason. But I disagree. It has better image quality than the M8 does when used with fine Leica lenses. And you can pick up two E-P1s (or a GH-1), a few adapters and 5 or 6 nice lenses for the price of an M8.

Roger Cicala"

Corner sharpness yet to be determined...

Thanks everyone,

My perpetual anguish about whether to upgrade to D300 or D700 in now leaning towards D300... today

G'day Mary,

I was trying to make a similar decision, but in the end I have decided to take the soft option and not make a decision until I see if Nikon release the much-rumoured D700X.

Yes, I have also taken the soft option. Now I can sleep at night!

A very profound uw photographer gave me some advice...

"patience my pet"

then

"buy the very best you can't afford"

The simplest term I guess -

Film doesn't mind light hitting it at an oblique angle (i.e. not right angle).

Wide angle lenses typically have light rays arriving at the film plane at an oblique angle, telephoto usually right angle to film plane.

Sensors it appeared do not like lights come at an oblique angle, the analogy of well is good. Apparently it is due to the anti-aliasing (AA) filter. This bit I sort of understand but can't tell you more.

So old film lenses mostly vignette at the corners. My understanding is that sharpness is not really affected, but the corners darken.

This issue of older lenses not fitting well in FX, plus my investment in Tokina 10-17, Sigma 10-20, and the 1.5x effect on tele lenses have so far stopped me from thinking beyond my beloved D300 for now.

My take is that along the way I will add new lenses and some day FX Nikons will not cost so much as today, I will then take the plunge.

Yes, I have also taken the soft option. Now I can sleep at night!

 

A very profound uw photographer gave me some advice...

 

"patience my pet"

 

then

 

"buy the very best you can't afford"

Having seen that drysuit that you wore for many years that was a walking add for Aquaseal I can tell that you only ever applied that last line to your UW photography gear though!

Having seen that drysuit that you wore for many years that was a walking add for Aquaseal I can tell that you only ever applied that last line to your UW photography gear though!

Hang on just a minute.... do I know you?

Mary

Hang on just a minute.... do I know you?

 

Mary

Yep! You even took a photo of me underwater once - I think I was shooting video at the time. Haven't seen you for probably ten years though. Are you still a postie?

I know its you Kent. Stingray housing, Oceangraphics lights, drysuit, Bicheno.

14 years actually, 29/10/95, I still have the shots.

Red sea dreaming gave you away.

Mary

I know its you Kent. Stingray housing, Oceangraphics lights, drysuit, Bicheno.

 

14 years actually, 29/10/95, I still have the shots.

 

Red sea dreaming gave you away.

 

Mary

Hey Mary, how are you doing? Time certainly flies!

From memory we had nachos at the pub afterwards too.

I think this is the kind of pixel peeping that is interesting in engineering but not really relevant to photography. Certainly FX sensors will get better over time but the advantages to underwater photography over film are tremendous. The small issues with film vs digital quality are miniscule. You don't really care what is going on in the extreme corners. Your subject shouldn't be there. In fact you often want the corners out of focus to draw your eye toward what is really important. The corners will have slight vigenetting and dome ports will likely add distortion there anyway. I doubt any of this will be detectible anyway in the real world and if it is its likely as much an advantage as a disadvantage anyway.

I don't want to go back to the stone age. Digital capture allows me the tools to get what I really want in the frame, w hich is what really matters.

--Shoot hundereds of shots on a single dive

--Instant preview to review and adjust: composition, lighting, exposure settings, focus

--Live Preview for composing in awkward angles--this IS important UW

--Very high ISO capability to handle low light WAY better than film. (That's the advantage of FX)

--Better selection of fast WA lenses for low-light shooting (another advantage of FX)

--Easier and more powerful manipulation of images to fine tune technical issues than film through RAW processing

--EXIF data to help you learn

Have you ever shot an entire roll of garbage shots on film. There's nothing more frustrating than that when trying to learn.

Leave the technical issues up to the engineers, or join in onthe discussion for the fun of it. But don't base photographic decisions on this kind of minutia. If you can afford FX and the lenses to go with it then go for it, I'm sure you won't be dissappointed in the results. If not then DX will serve you very very well I'm sure you won't be dissapointed either. Just look at all the stuff Alex Mustard published on his D70!