Fx vs Dx Comparisons

Marcel

Marcel

Happily retired
Staff member
Super Mod
Obir said:
I prefer #2 from the first set and #1 from the second...
Not exactly sure why, but the color rendition and detail seems to appeal more to me on those.:confused:
Should I start saving for a d700? :)
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It might have something to do with sensor's pixels size, but I still very much enjoy images that I take with the D90 in good light and low iso. There seem to be more color depth with the D7000 sensor but I have to be very careful with shutter speeds and camera holding technique.
 
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gqtuazon

Gear Head
Marcel said:
OK guys, time for truth.

In both cases, shot ONE is….(drum roll) FX

Where it gets interesting is that for the DX shots, the table was with the D90 and the 35-70 2.8, and for the second one it was the D7000 with the 17-55 2.8. So, since the baker shot was reduced in size, you can see the baker is a tad larger than the FX shot made with the D700.

Thanks for your interest with this "non scientific" experience.
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I should have followed my instinct. Thanks for doing the challenge for us Marcel.
 
Marcel

Marcel

Happily retired
Staff member
Super Mod
gqtuazon said:
I should have followed my instinct. Thanks for doing the challenge for us Marcel.
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Thanks for the comments and participation Glenn. I guess my point was to prove it is difficult to evaluate quality in this reduced size of picture on the web. Maybe if we had access to a place to upload larger files the difference would be more apparent.

But, for amateurs (someone not earning his living selling prints), I think we are very well served with either DX or FX. It all depends on the iso we need and the size we want to print.
 
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Obir

Senior Member
Marcel said:
OK guys, time for truth.

In both cases, shot ONE is….(drum roll) FX

Where it gets interesting is that for the DX shots, the table was with the D90 and the 35-70 2.8, and for the second one it was the D7000 with the 17-55 2.8. So, since the baker shot was reduced in size, you can see the baker is a tad larger than the FX shot made with the D700.

Thanks for your interest with this "non scientific" experience.
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That is one nice (and expensive) lens you used for the shot with the d7000...
Does that lens have VR ? Was it on when you took the shot?
 
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Obir

Senior Member
Marcel said:
No VR on that lens. I got it pre-owned at a bargain price.
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Nice:)
Guess I wouldn't be able to see a difference in sharpness or detail on the second set if VR, tripod, or a higher speed was used on the shot from the d7000 (dx camera).
I could barely see a difference in detail on the first set...and I got it wrong!!!LOL:)
 
Marcel

Marcel

Happily retired
Staff member
Super Mod
AperturePriority said:
Marcel,

Either you moved the tripod or zoom out to get the same FOVs, you did make DoF of DX thicker. And, it cannot be hid. ;)
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I stayed in the same spot for the first shot and had different lenses on FX and DX I adjusted the zooms to get the same view and shot at the same f stop. This is why the DX has more DOF (shorter lens same f stop). But I'll try to repeat the experiment with different f stops to make the DOF the same and then we shall see if the difference can be seen.
 
A

AperturePriority

New member
Marcel said:
I stayed in the same spot for the first shot and had different lenses on FX and DX I adjusted the zooms to get the same view and shot at the same f stop. This is why the DX has more DOF (shorter lens same f stop). But I'll try to repeat the experiment with different f stops to make the DOF the same and then we shall see if the difference can be seen.
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Can not do that, Marcel:

You know that with the same lens, different aperture gives you different resolution?
The larger apertures give you more sharpness than the smaller in pictures!
Pictures taken with f/4 are sharper than the ones taken with f/5.6!
 
Marcel

Marcel

Happily retired
Staff member
Super Mod
AperturePriority said:
Can not do that, Marcel:

You know that with the same lens, different aperture gives you different resolution?
The larger apertures give you more sharpness than the smaller in pictures!
Pictures taken with f/4 are sharper than the ones taken with f/5.6!
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But what if I used a better lens with the larger opening… Maybe this way only DOF would be affected. Remember that I'm not implying anything scientific with this thing.
At the risk of repeating myself, it wasn't a contest and there were no door prizes. I just wanted people to see that they probably had great tools to produce great images and with the size of pictures posted on our forums, it's amost impossible to evaluate quality at the pixel peeping level.

But for those who print their work for exhibits it's a whole other game. When you look at identical size prints side by side, there is no way you won't notice the quality difference if there is one.
 
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AperturePriority

New member
Marcel said:
Wouldn't that be the other way around? ;)
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No Marcel,

A lot of photographers confused and misunderstood that:

When you close down the lens aperture, you gain more DoF. But you will loose sharpness.
Pictures taken by a given lens and given format at f/4 have thinner DoF and better sharpness than the one taken at f/5.6.
Gaining DoF costs you the sharpness of images. You have to pay for it. Nothing is free!
 
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AperturePriority

New member
Marcel said:
But what if I used a better lens with the larger opening… Maybe this way only DOF would be affected. Remember that I'm not implying anything scientific with this thing.
At the risk of repeating myself, it wasn't a contest and there were no door prizes. I just wanted people to see that they probably had great tools to produce great images and with the size of pictures posted on our forums, it's amost impossible to evaluate quality at the pixel peeping level.

But for those who print their work for exhibits it's a whole other game. When you look at identical size prints side by side, there is no way you won't notice the quality difference if there is one.
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I take your words of the text in bold. And we all know that for enlargement printing works, there are differences between two formats. But how much different between them that one has to go with FX is depend on the needs of each one of us.
 
W

westmill

Banned
Marcel said:
Great observation. Maybe next time I'll play with f stops to make the DOF the same. Then we'll see if people can see the difference on the web. Probably if I was to post the original files there might be more difference. But in good light and low iso, FX and DX are not that much different IMHO.
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Well we know there is no differance between between the D300 and D700 upto 800 ISO. What would be realy realy intresting, is
seeing if the D7000 has caught up with the D700 at higher ISOs ? Do some at 1600 ISO and 3000 ISO !!!!!
That would be very intresting indeedy lol
 
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westmill

Banned
AperturePriority said:
No Marcel,

A lot of photographers confused and misunderstood that:

When you close down the lens aperture, you gain more DoF. But you will loose sharpness.
Pictures taken by a given lens and given format at f/4 have thinner DoF and better sharpness than the one taken at f/5.6.
Gaining DoF costs you the sharpness of images. You have to pay for it. Nothing is free!
Click to expand...
Ouch ! sorry.... but you have that soooooo wrong. Virtualy all lenses perform at there best when closed down 2 to 3 stops.
Wide open performance has the narrowest DOF and usualy low sharpness especialy at the edges. F1.4 lenses genraly peak at around
F4 for maximum resolution where slower lenses like F4 will perform best around F8. Sharpness only starts to deteriate when difraction kicks in.
Diffraction doesnt genraly kick in until about F11 on your average lens.
 
A

AperturePriority

New member
westmill said:
Ouch ! sorry.... but you have that soooooo wrong. Virtualy all lenses perform at there best when closed down 2 to 3 stops.
Wide open performance has the narrowest DOF and usualy low sharpness especialy at the edges. F1.4 lenses genraly peak at around
F4 for maximum resolution where slower lenses like F4 will perform best around F8. Sharpness only starts to deteriate when difraction kicks in.
Diffraction doesnt genraly kick in until about F11 on your average lens.
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I am not wrong here, westwing!
I easily agree with you in general, sweet spot of a lens is about 1-2 fstops closed down. That happens because of technical limitations of the those lens designs. For good designed (nocturnal, for example) lenses, the more you open the lens, the sharper you get in your images.

And for the 300mm AF-S with wide open f/4 the sharpness you can see from edge to edge.
The best sharpness of a 58mm 1.2 Noct is at f/1.2, not at f/4, 5.6, or 8...
 
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Eye-level

Banned
When you stop down a lens you gain DOF...when you open it up your DOF is thinner...the Noct Nikkor is razor sharp even wide open and even out to the edges with very little light falloff...that is why it is so damn expensive...
 
W

westmill

Banned
AperturePriority said:
I am not wrong here, westwing!
I easily agree with you in general, sweet spot of a lens is about 1-2 fstops closed down. That happens because of technical limitations of the those lens designs. For good designed (nocturnal, for example) lenses, the more you open the lens, the sharper you get in your images.

And for the 300mm AF-S with wide open f/4 the sharpness you can see from edge to edge.
The best sharpness of a 58mm 1.2 Noct is at f/1.2, not at f/4, 5.6, or 8...
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Im sorry but you are totaly wrong here.
Yes you get the occasional lens that happens to perform well wide open, but they are still better closed down a
little. The 300 F4 is a corker wide open at F4 but thats because in part its a simple design and F4 not F2.8.
Nikkor AF-S 300mm f/4D IF-ED - Review / Test Report - Analysis
 
Marcel

Marcel

Happily retired
Staff member
Super Mod
Eye-level said:
When you stop down a lens you gain DOF...when you open it up your DOF is thinner...the Noct Nikkor is razor sharp even wide open and even out to the edges with very little light falloff...that is why it is so damn expensive...
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I wasn't thinking about this particular lens that is amazing. For ordinary lenses, I have to agree with westmill that closing down a few stops usually gets more sharpness until you get passed f11-16 where diffraction takes over and eats up sharpness.
 
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