# aperture to use for landscape with the Tamron 17-50 f/2.8 non-vc lens?



## lance70 (Jun 19, 2012)

Hi..... I just purchased a Tamron 17-50 non vc lens to use with my D90, I wanted to see what aperture you recommend for landscape pictures in CO with this lens? Thank you


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## AaronLLockhart (Jun 19, 2012)

lance70 said:
			
		

> Hi..... I just purchased a Tamron 17-50 non vc lens to use with my D90, I wanted to see what aperture you recommend for landscape pictures in CO with this lens? Thank you



This is just personal preference, but I always use a small aperture (f/16 or higher) and super long exposure on 100ISO. I also like a wide angle when doing landscapes.

Nikon D5000 | 18-55mm AF-S VR | 50mm 1.8G | HB-47 Hood


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## Solarflare (Jun 19, 2012)

I would recomment against f/16 and higher on a digital camera if in any way avoidable. Anything above f/8 causes reduction of resolution through diffraction. Thats really rather something you would want to use with a 4x5" camera who can run much lower apertures than digital cameras, without diffraction.

Also, wide lenses have a very large depth of field. So if you stay near 17mm, you probably dont need such a low aperture like f/16. Just dont try to photograph the ground directly in front of the camera as well, but keep a bit of distance to it.


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## BXPhoto (Jun 19, 2012)

Solarflare said:


> I would recomment against f/16 and higher on a digital camera if in any way avoidable. Anything above f/8 causes reduction of resolution through diffraction. Thats really rather something you would want to use with a 4x5" camera who can run much lower apertures than digital cameras, without diffraction.
> 
> Also, wide lenses have a very large depth of field. So if you stay near 17mm, you probably dont need such a low aperture like f/16. Just dont try to photograph the ground directly in front of the camera as well, but keep a bit of distance to it.



Great Advice. The tamron starts to fall apart after f11 for sure. I would set the camera up to somewhere between f/5.6-f/8 and focus to infinity.


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## JG_Coleman (Jun 19, 2012)

lance70 said:


> Hi..... I just purchased a Tamron 17-50 non vc lens to use with my D90, I wanted to see what aperture you recommend for landscape pictures in CO with this lens? Thank you



There's honestly no hard and fast rule... it all depends on the depth of the scene you're working with, the detail and size of the foreground objects, etc... basically, it depends upon your vision for the shot.  Most often, landscape shots benefit from the deep focus of small apertures.  But not all landscape/nature shots are enormous, sweeping vistas... and sometimes an excessively deep focus achieved with a tiny aperture is not only over-kill, but can also produce a slightly degraded photograph as compared to one taken with a larger, more appropriate aperture for the depth of the actual scene.

Traditionally, deep landscapes usually get the low-ISO/small aperture approach as mentioned by Aaron.  Smaller apertures mean great depth-of-field, so most all of the objects in the frame, from the foreground elements to the distant background elements, will be in focus.  In many cases, this is ideal.

However, there's a trade-off in that small apertures will rob you of some measure of sharpness due to diffraction.  So, if a certain shooting situation truly doesn't require a tiny aperture, then you'd be better of using a bigger aperture and retaining more sharpness.  For example, in a relatively shallow landscape scene, you might achieve effective depth-of-field with an aperture of f/11 and get a considerably sharper shot.

With landscape photography, you've got to take a moment to assess any given scene and determine the proper balance between wide depth-of-field (the smaller the aperture, the great DOF) and sharpness at the focus point (sharpest apertures are generally between f/8 and f/11, falling off noticeably in sharpness at f/16 or so).

PS - I see now that alot of you guys beat me to these points while I was writing.


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## KmH (Jun 19, 2012)

Yep. Diffraction will negatively impact image quality and the smaller the lens opening (f/11 and smaller like f/16, f/22, f/32, etc). Diffraction Limited Photography: Pixel Size, Aperture and Airy Disks

To mitigate diffraction, landscape photographers rely on the hyperfocus distance and using depth-of-field (DoF) to their advantage. Back in the day, lenses had hyperfocus scales on them, but the advent of digital, auto this, and auto that not only have hyperfocus scales gone away, many lenses today don't even have focus distance scales.

To learn more about hyperfocus, DoF and how to use them see - Understanding Your Camera&#8217;s Hyperfocal Distance
Understanding Depth of Field in Photography


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## JG_Coleman (Jun 19, 2012)

Solarflare said:


> Also, wide lenses have a very large depth of field. So if you stay near 17mm, you probably dont need such a low aperture like f/16. Just dont try to photograph the ground directly in front of the camera as well, but keep a bit of distance to it.



Wide lenses, for the most part, have the same inherent depth-of-field characteristics as any other medium-angle lens.  They just have a greater "apparent" depth-of-field because out-of-focus background elements are rendered so distant in the photograph that you cannot easily tell that they are out-of-focus.  I guess I'm not really refuting your statement that you can use larger apertures with a wide-angle because, indeed, super-wide angle lenses can take shots that appear very sharp throughout using f/8 - f/11... but it's instructive to understand that there is no magical DOF properties built into a wide-angle that somehow make it function differently from other lenses.



Solarflare said:


> Just dont try to photograph the ground directly in  front of the camera as well, but keep a bit of distance to it.



I can't say I'm on board with this, though.  Having interesting foreground elements is, in many cases, an integral part of landscape photography... especially landscape photography with wide-angle and super-wide-angle lenses.  For this very fact, the OP needs to put in a bit more work assessing the appropriate aperture and shouldn't just blindly default to f/8-f/11 simply because they are using a wide-angle.  For example, if you've got a foreground element that is VERY close-by (say, 2 feet away), then sometimes f/8 will leave you with noticeably indistinct detail in the background elements that is not desirable.


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## TCampbell (Jun 19, 2012)

When you increase the f-stop (to get a smaller aperture) you do increase the depth of field -- increasing the focused area.  For a landscape shot, you're not necessarily focusing on one thing because the overall scene becomes the subject. 

To maximize the focus on the overall scene, you can manually focus the lens to the "hyper-focal distance".  The hyper focal distance can be calculated for any given focal length and f-stop.  To find the hyper focal distance, you used to use the DoF marks on the lens.  But on modern auto-focus lenses, they seldom seem to include these anymore (several of my prime lenses have them, my zoom lenses do not.)  But you can use a table or calculator to find it.  There's an online calculator at DoFmaster.com and there are apps you can download if you own a smartphone which will calculate it (btw, DoFmaster writes apps, and there's a nominal charge to buy it.  But I've discovered there are DoF calculator apps that are free.)

For example, if you were using an APS-C crop-frame body, an 18mm focal length, and f/16, then you'd focus the lens to about 3.5' at which point everything from a little less than 2' out to infinity will be in focus.  If you change the aperture to f/8 then you'd focus the lens to just about 7' and everything from roughly 3.5' to infinity will be in focus (which means depending on how you've framed up the shot, you may actually slight soft content in the extreme foreground.)

Depth of fields are only this large because of the 18mm focal length.  If you were to change to, say, a 30mm focal length, then the hyper focal distance jumps to about 20' at f/8 and anything much closer than 10' will appear soft.  But if you bump back up to f/16 then the hyper-focal distance drops to about 10' and everything from about 5' to infinity is in focus -- and with a 5' near-limit on the DoF you may not notice any out of focus areas depending on how you've framed the shot.  

As for diffraction... the problem is certainly real, but it's also something you won't see unless you print big or crop in tight on a small section.  

Due to the wave nature of light, it doesn't technically focus to a pinpoint.  It focuses to an "Airy disk".  As the aperture gets tinier, the Airy disk size increases.  As the Airy disks increase such that they now overlap adjacent pixels on the sensor (Technically sensors don't have "pixels" they have an array of "photo sites" constructed in the pattern of a bayer mask, but the concept of what the Airy disk does on the sensor still applies.), the camera can no longer resolve the difference between those points resulting in a slight loss in "effective" resolution.  But note that when we talk about acceptable focus within the depth of field, we're not talking about 1 point of light resolving to a single pixel on the sensor... we're talking about what the human eye would notice and consider as acceptable focus.  That depends on how much you magnify the image when it's displayed.  

If you need more depth of field, go ahead and crank up that aperture to a high f-stop.  Don't fear f/16... or 22 or 32 for that matter.  Just know that as you use those highest f-stops you won't be able to resolve the image down to the single pixel level anymore and that could be noticed if you crop in very tight or print the image very large.   But most people don't print large enough or crop in tight enough for this to be the case.

This, btw, is the whole Nikon D800 controversy.  At 36 megapixels, the "pixels" (really photo-sites) are so tiny that the Airy disks don't have to be very large before they overlap and the camera becomes diffraction limited.  This doesn't mean the camera produces blurry images.  It simply means that there's a point where the extra megapixels stop providing more resolution and you may as well have been shooting with a lower resolution camera.    The images produced will be fine... they just won't necessarily be "better" than a camera with lower resolution (when shooting at a high enough f-stop for the diffraction issue to come into play.)


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## AaronLLockhart (Jun 19, 2012)

Pardon my ignorance, but isn't that what lens hoods are for; to stop diffraction?

Nikon D5000 | 18-55mm AF-S VR | 50mm 1.8G | HB-47 Hood


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## JG_Coleman (Jun 19, 2012)

Lens hoods just prevent lens flare and other similar problems caused by light striking the lens at a poor angle.  They have nothing to do with diffraction.


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## BXPhoto (Jun 19, 2012)

Also good for protecting the lens from bumps etc...


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## TCampbell (Jun 19, 2012)

If you want a good example of diffraction, check this article (at Luminous Landscape):  Understanding Lens Diffraction

They took a photo of a subject on a solid tripod, using a remote release, on a non-windy day (e.g. the lens is focused perfectly and they did not change focus between shots and there is absolutely no motion blur.)  So the only "blur" you see, is caused by diffraction. 

Note that these are 100% crops -- so when you look at the difference between f/5.6 and f/22 you can see the loss in resolution at a 100% crop.  But it's not such a great loss that it would be obvious to the human eye if it wasn't cropped in so tightly.  (BTW, I noticed that while the article says they took an exposure at every f-stop, they somehow skipped f/16 -- that or they forgot to publish it.)

There's a ink at the end of the article that takes you into the details of WHY diffraction happens.  So once you see an example of what diffraction is... to understand how it works, don't forget to click the link to the next page and keep reading.


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## AaronLLockhart (Jun 19, 2012)

Alright, would diffraction occur in night shooting?

Nikon D5000 | 18-55mm AF-S VR | 50mm 1.8G | HB-47 Hood


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## JG_Coleman (Jun 19, 2012)

AaronLLockhart said:


> Alright, would diffraction occur in night shooting?



Yes, no differently than it would occur in the daytime or indoors.

I think you may be confusing "refraction" and "diffraction".  Lens hoods, for example, help prevent artifacts like lens flare caused by _refraction_.


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## AaronLLockhart (Jun 19, 2012)

JG_Coleman said:
			
		

> Yes, no differently than it would occur in the daytime or indoors.
> 
> I think you may be confusing "refraction" and "diffraction".  Lens hoods, for example, help prevent artifacts like lens flare caused by refraction.



You are correct. I tend to get things backwards from time to time. Just be patient with me 

I was thinking that lens flare was diffraction, but the I thought about refracted light in water or even through window glass, and it all made sense to me after that.

Thank you for clarifying.

Nikon D5000 | 18-55mm AF-S VR | 50mm 1.8G | HB-47 Hood


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## Helen B (Jun 19, 2012)

Luckily, lens hoods have no effect on refraction. They simply reduce the amount of light from objects outside the frame.


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## JG_Coleman (Jun 19, 2012)

Helen B said:


> Luckily, lens hoods have no effect on refraction. They simply reduce the amount of light from objects outside the frame.



Huh, guess I learn something new everyday.  I always thought lens flare was an example of refraction... which seems to be a misunderstanding in terminology that I share with plenty of people (its remarkable how many people refer to flare as "refraction").  Needless to say, I had to immediately go googling for technical information about lens flare after reading your post and, not surprisingly, you're right... lens flare is not refraction, but reflection.

I thought it was funny though that every technical article online about lens flare is very clear about saying that lens flare is NOT refraction at all, yet just about every forum post, blog post, content-factory article that pops up in the search results use "refraction" and "lens flare" as if they are synonyms.  This reminds me of the good old "PPI vs. DPI" debacle that some people get so worked up about.

So, AaronLLockhart, lens flare is just plain, old, not-scientific-sounding "reflection"... not "refraction" as I previously stated.

Thank you, Helen.


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## Joshonator (Jun 19, 2012)

It should also be noted that the optimal aperture in terms of sharpness depends on the lens to some extent.


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## AaronLLockhart (Jun 19, 2012)

So let me make sure I understand what's being said here. By what you are saying, diffraction will increase with longer focal length?

Nikon D5000 | 18-55mm AF-S VR | 50mm 1.8G | HB-47 Hood


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## TCampbell (Jun 19, 2012)

And of course "diffraction" and "refraction" aren't exactly the same things either.  The physics of diffraction are based on the assumption that the lens is optically perfect -- so we aren't really talking about how well the optical glass can refract light or whether one lens is better than another.  "Diffraction" happens when light is forced through a tiny area and then needs to spread out.  Refraction happens when light contacts a transparent surface/air transition at an angle (such as the two sides of a lens element) and the light bends as it passes through the transition.


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## Nat. (Jun 19, 2012)

I don't think it does.

Here's an article on diffraction: Diffraction Limited Photography: Pixel Size, Aperture and Airy Disks

Quote:

_*Technical Note: Independence of Focal Length*
Since  the physical size of an aperture is larger for telephoto lenses (f/4 is  has a 50 mm diameter at 200 mm, but only 25 mm diameter at 100 mm), why  doesn't the airy disk become smaller? This is because longer focal  lengths also cause light to travel further before hitting the camera  sensor -- thus increasing the distance over which the airy disk can  continue to diverge. The competing effects of larger aperture and longer  focal length therefore cancel, leaving only the f-number as being  important (which describes focal length relative to aperture size)._


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## table1349 (Jun 19, 2012)

To the OP.  A series of landscapes with the 17-50 at various f stops: f11, f16, f22.  You decide what you think will work for your situation. 

photoSIG » Blue Spring Day in Sydney
photoSIG » Heavens Glory
photoSIG » Rays of Dawn


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## Joshonator (Jun 19, 2012)

From my understanding of physics, refraction cannot be controlled since it depends of how good the glass is. I think the glass is usually a fast medium and doesn't cause too much refraction (and if it does the only thing you can do is clean the lens or get a new lens). Whereas diffraction is directly dependant on the size the aperture hole.

Diffraction can cause light waves to overlap and interfere which in the case of light hitting the sensor, will leave a lack of detail (tiny gaps in light getting to the sensor).


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## Helen B (Jun 20, 2012)

Joshonator said:


> From my understanding of physics, refraction cannot be controlled since it depends of how good the glass is. I think the glass is usually a fast medium and doesn't cause too much refraction (and if it does the only thing you can do is clean the lens or get a new lens).  Whereas diffraction is directly dependant on the size the aperture hole.
> 
> Diffraction can cause light waves to overlap and interfere which in the case of light hitting the sensor, will leave a lack of detail (tiny gaps in light getting to the sensor).



A lens focuses light _because_ there is refraction at the air/glass and glass/glass surfaces. Refraction is not a bad thing in a lens, it is a good thing - essential in fact. The lenses we commonly use work because of refraction.

Destructive interference ('gaps') caused by diffraction is rarely a problem in normal photography because the light arriving at the aperture is not usually coherent - ie the 'overlaps' of light heading to _two different image points_ caused by diffraction rarely cause destructive interference because the overlapping light in this case is not usually at the same frequency and in a constant phase relationship. The effect is generally to spread light that should have focused to a single point into a spread-out interference pattern with a central disk (the Airy disk) surrounded by rings (all of which is the Airy pattern). The loss of (otherwise possible) detail happens not because of gaps but because image points are spread into disks. Of course there are other factors in a real lens that will also cause a point to spread (such as lens aberrations, defocus etc) so diffraction simply sets a minimum possible amount of spread.


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## AaronLLockhart (Jun 20, 2012)

Helen B said:
			
		

> A lens focuses light because there is refraction at the air/glass and glass/glass surfaces. Refraction is not a bad thing in a lens, it is a good thing - essential in fact. The lenses we commonly use work because of refraction.
> 
> Destructive interference ('gaps') caused by diffraction is rarely a problem in normal photography because the light arriving at the aperture is not usually coherent - ie the 'overlaps' of light heading to two different image points caused by diffraction rarely cause destructive interference because the overlapping light in this case is not usually at the same frequency and in a constant phase relationship. The effect is generally to spread light that should have focused to a single point into a spread-out interference pattern with a central disk (the Airy disk) surrounded by rings (all of which is the Airy pattern). The loss of (otherwise possible) detail happens not because of gaps but because image points are spread into disks. Of course there are other factors in a real lens that will also cause a point to spread (such as lens aberrations, defocus etc) so diffraction simply sets a minimum possible amount of spread.



So, ultimately it's unavoidable, even with a super clear glass?

Nikon D5000 | 18-55mm AF-S VR | 50mm 1.8G | HB-47 Hood


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