Need some advice from the pros

[WayneF]

Diffraction is not a lens aberration I beg to differ...

Differ all you want, but until you give a suitable argument how that possibly could be remotely true, you ain't said nuthin'.

Diffraction is an edge effect (could be a slit), but it is the edge of the aperture in the lens. It certainly is NOT the sensor.

 

[Eye-level]

Diffraction is the spreading of an image point caused by light rings which are formed by the rays bent at the edges of a stop...you cannot correct diffraction with the design of the lens nor by closing the diaphragm.

IT IS NOT A LENS ABERRATION damnit!!!

​There I think I said enough that time...I think you are the one who has said a bunch of nonsense!

 

[Akiviri]

I think I'll just say "The proof is in the pudding" and leave it at that. Intellectual arguments aside - at 100% crops (by default NOT enlargements of the image itself), the difference is clear.

 

[WayneF]

Sorry, diffraction is caused by only the lens aperture.

You are right only in this degree: Opening the f/stop (wider aperture) makes the edge effect be less significant, less of the total light passing through is affected by the edge - whereas stopping it down makes diffraction much more significant (much more edge effect to total area). It absolutely is 100% caused by the lens aperture.

Not sure I would name it an aberration, as much as a property... that is, it cannot be corrected, Wider aperture is better though, in this one property.


When a photo lens test report shows the measured resolution dropping off the more it is stopped down, what do you imagine causes that?

When a smaller telescope has less theoretical resolution (larger Airy Disk) than a larger one, why do you imagine that is?

Greater diffraction is why that is. It has nothing to do with the sensor.

 

[Eye-level]

Doesn't have a damn thing to do with the lens thank you very much...

Let me put it to you plain and simple and stupid...

I used to own a Contaflex Super...great camera...body with a BUILT IN APERTURE and SHUTTER BLADES that mounted lens that was just that a LENS NO APERTURES.

Guess what soldier?

The snaps exhibited DIFFRACTION when you stopped it down past it's critical focusing point...

Diffraction IS NOT AN ABERRATION OF THE LENS!!!!!!!!

 

[Eye-level]

How bout even more simple and stupid...

NOT ALL LENSES HAVE A DIAPHRAGM!!!!

​

 

[Dave_W]

I'm not sure you can have a lens without an aperture since an aperture, by definition, is the point at which the light leaves the lens, right?

 

[jwstl]

Diffraction is a lens issue in that it occurs when lights passes through a small opening and in photography that's usually the lens. And in digital photography, the sensor does make a difference. But it has nothing to do with the sensor size or resolution; its the pixel size. Here's the article that really helped me understand it....

http://www.cambridgeincolour.com/tutorials/diffraction-photography.htm

 

[WayneF]

Let me put it to you plain and simple and stupid...

I used to own a Contaflex Super...great camera...body with a BUILT IN APERTURE and SHUTTER BLADES that mounted lens that was just that a LENS NO APERTURES.

Guess what soldier?

The snaps exhibited DIFFRACTION when you stopped it down past it's critical focusing point...

Diffraction IS NOT AN ABERRATION OF THE LENS!!!!!!!!

Not at all familiar with it, but you said built in aperture, whatever that is. It would be hard to believe much of a camera would not have adjustable f/stop - but I suppose you just mean a fixed non-adjustable aperture. Brownie box cameras were like that. Nevertheless, that lens had a diameter, adjustable or not, so there was diffraction there, caused by it.

How bout even more simple and stupid...

NOT ALL LENSES HAVE A DIAPHRAGM!!!!

​

All optical lenses have a diameter, and thus they have an aperture. It may not be adjustable, but they definitely all have a computed f/stop number for that aperture. Mirror lenses for example. They say f/8 or something. They have a diameter, which causes diffraction.

Even Telescopes, same thing. It may not be adjustable, but their diameter is the aperture.

If you want to discuss it, you ought go read up on this first.
Start here: http://en.wikipedia.org/wiki/Airy_disk

 

[Eye-level]

I'm not sure you can have a lens without an aperture since an aperture, by definition, is the point at which the light leaves the lens, right?

There are literally tons of them I bet...by definition aperture is a lens opening controlled by a DIAPHRAGM!

NO CONTAFLEXES ARE NOT FIXED APERTURE LENSES...THEY HAVE BUILT IN SHUTTERS AND DIAPHRAGMS and guess what???

DIFFRACTION HAS NOTHING TO DO WITH THE LENS!!!!

With that I am done...go on believing the BS if you want folks...no sweat off my back...

 

[Sambr]

Why in the hell don't you techno wizards -just go out and shoot? I read all this theory goop, yet there is NO photos to prove it from the OPs. One of my favorite lens is the Nikon 28-300Vr - it get's nasty reviews, about all it's distortion and softness etc. LOL why do get (I don't mean to brag) award winning photos from it? Think about that. People like to try to "impress" others with technical BS which may or may not be relevant in real word situations.

 

[Dave_W]

I'm not really sure what you're talking about Sambr, since no one on this thread is out to "impress" anyone else, except maybe the statement about award winning photos. What I see here is a difference of opinion and a discussion therein. You know, the nice thing about a forum like this is that we can all express ourselves openly like adults (most of the time) and members who don't care for the discussion or the subject matter have no obligations to read the thread.

 

[Sambr]

I'm not really sure what you're talking about Sambr, since no one on this thread is out to "impress" anyone else, except maybe the statement about award winning photos. What I see here is a difference of opinion and a discussion therein. You know, the nice thing about a forum like this is that we can all express ourselves openly like adults (most of the time) and members who don't care for the discussion or the subject matter have no obligations to read the thread.

Yes your right Dave, and I expressed mine. I stand by my feelings.

 

[jwstl]

We should probably create a new thread on the diffraction topic for those interested since it is outside the scope of the original topic in this thread. And Sambr can avoid that one and start one on award winning photos with the 28-300.

 

[Sambr]

We should probably create a new thread on the diffraction topic for those interested since it is outside the scope of the original topic in this thread. And Sambr can avoid that one and start one on award winning photos with the 28-300.

Too funny however if it makes you happy go for it.

 

[Rick M]

Lol, Sam does has some great shots from that nightmare of a lens

 

[Rick M]

Anyway you want to look at this it seems to come down to resolution vs. diffraction. Does the smaller pixels out resolve the negative effects of diffraction. Pick your poison .

My non-technical opinion:

I'll take the larger pixels of the Fx sensor for landscape photography. Having shot with both Fx and Dx, the proof is in the print (or screen). I was amazed the first time I opened up an Fx image at 100%, just blows away Dx.

 

[Akiviri]

Resolution - Larger sensor wins every time.

Diffraction - it isn't either/or - it's both/and. As usual.

I'm done with this thread now - GL OP.

 

[mikeh32217]

Thanks y'all for your advice, I have a few months before I'll be able to afford so will take what you've advised and research further.

 

[AC016]

Why am i not surprised that this thread got de-railed like it did? lol Yes, after thinking about your post a bit more, i realised i did not pick up on the "landscape" bit. FX would suit that genre better. Let me tell you why with a bunch of techno babble....... lol, no, i won't bore you to death. I think you will make the right decision for yourself. Good luck and let us know what the outcome is.