CAMERAS: Can someone PLEASE show me the difference between f2.8 and f4.0 at 50mm?? (photos)?

Question

I'm looking for actual photo samples... not a wizeguy showing me a photo of a lens with 2.8 shown on it.. OR at least some words on what you think regarding this. The "pros" that I know are telling me.. ohh. huh. i never eally do 2.8.. i guess i could try it and see what happens. Some camera shops.. don't even get that 11 is a smaller aperture than 6.. blows my mind.

Do I spend the extra money on the 2.8 capable of being fixed throughout the focal length.. vs. getting a 3.5-5 or6. looking at lengths between 50-200mm. I know it will allow for more light ... but not as much of an issue as I want blowout or blur out.. whatever ya call it - trying to achieve smallest depth of field for outdoor portrait photography. I'm just not sure it's worth the extra $ for a beginning amatuer with minimal clients or not. Next lens after this one? Probably a different body camera and lens. So I want something that will last me a bit with this camera... and work as a backup camera

Answer 1

You won't really learn much by looking at samples. What you would need to do is use the lens in the field and see if you gained some versatility with the fixed aperture lens.

Since you are looking at a 50-200 lens, you would need to see several comparisons made under indentical conditions. You would need to see a subject at 10 feet away with each lens and then one at 20', 50', etc. Repeat this for various focal lengths. You would end up with 100 comparison shots.

Since you say you are looking for a lens for outdoor portrait photography, that narrows it down somewhat. If you were doing all head shots, you could just get a fixed lens and know for sure what your results would be. I imagine that you will be doing various poses and various crops in the outdoors, though.

Depth of field is also a function of the working distance between the camera and subject, so this adds more challenge to making up samples for you.

I would agree that an f/4.0 will be quite adequate for throwing the background out of focus in almost any situation. If you are a beginning amateur, consider the cheaper lens and abandon it only if you find that it is inadequate and you have made enough money from your photography to pay for the upgrade lens.

I don't know what make camera you are using, as I can't find but one 50-200 lens (Pentax), so it's not like you would have a choice. Maybe you meant a 55-200? If you have a Nikon, we have a few members who swear by the Nikkor 24-85mm f/2.8-4.0D IF Autofocus Lens ($565) for portrait and model work. It has the wide aperture that you want.

Answer 2

Let me see if I can restate your question and needs.

Needs: A good lens for outdoor poertrait photography that will produce the desired depth of field (blur for you).

Limited budget.

Want to use the camera (maybe) as 2nd body.

Doesn't need the lens speed.

Based on that, a zoom lens will be your best choice. Portraiture outdoors allows you a lot of creative choices that you don't have in a studio and a zoom lens is the most pragmatic way to address these opportunities. For instance, the stacking or compression effect of a telephoto can be used for striking effect in portraits with the right composition. Be creative.

I think your camera has the APC sized sensor, which means that your effective focal length will be the size of the lens times 1.6. For a zoom in the range of 50 - 200, that puts you at the bottom of what would be considered the portrait range of focal lengths and run you up from there. Also, you will be able to experiment and learn what the different focal lengths bring to a picture and that is valuable knowledge.

Personally, if your camera uses the Nikon D mount, I would opt for something like the Tamron AF 28-200MM F/3.8-5.6 XR Aspherical (IF) Macro. It's sharp, has nice contrast and is inexpensive. It will do what you want it to do and makes a nice walk around lens, too. Because it is also a semi macro lens, you can explore that area of photography and the 28 mm translates pretty much to a 50 mm lens with your sensor size.

The real advantage for you of a fixed aperture is that the Depth of Field will be constant over the zoom range. I am not sure you will find that important in pragmatic terms shooting outdoors.

With the money saved over a faster lens that probably will not bring you real benefit and buying an inexpensive lens that will deliver good results, you can use the money saved for a good dedicated flash (you'll use it), reflectors, etc.

That's my two cents for where you are in photography at this point in time and what you want to do.

Vance

Answer 3

Well, it seems you have at least a small amount of knowledge regarding photography.
To remember that larger f-numbers are narrower than smaller f-numbers, think of hunting, if you're a hunter. A twelve gauge is bigger than a 22 gauge.
As for your lens, the 50mm 1.8 lens is usually the best. It's the cheapest lens, new, out there. And also one of the best. It costs around $100-130, so it's not bad at all. A step up from this is the 50mm 1.4, $250, or the 85mm 1.4<--amazing. The 85mm 1.4 is also over $1000.
Anyway, the regular old 50mm compared to a 50-200mm lens can vary in several different ways. First off, the 50-200mm lens stops down to f-4. While the 50mm lens stops down to f-1.8 or f-2.8. This means, with the 1.8 or 2.8, you can open up the aperture wider for night photography. This also means you have better shallow depth of field. And lastly, just by opinion, the 55-200mm lens is really just for absolute beginners. Let me take a guess at your camera. A Nikon? Maybe a D40. Possibly a D40x or D80.

Answer 4

There are too many example to give. Aperture and the affected depth of field change depending on the focus point and the relative distance of objects to that point.

It's actually an easier concept to understand if you can draw pictures of it than to go around and take arbitrary snapshots.


In a nutshell a larger f/stop buys you:
1) More available light/faster shutter speeds in lower light situatons
2) Shallower depth of field at all focal lengths. Depending on the "creative" aspect of the image you are taking this may be a hinderance or a blessing. The closer to the image the focus point, the less will be in focus, the furthere away, the more that will be in focus.

Answer 5

No samples, but plenty of experience. F4 will give you pretty shallow depth of field and of course the longer focal length that you use the more the effect is amplified. If you don't worry about needing a "fast" lens (one that lets in more light) then I'd save the extra cash and go for the 3.5-4, it'll be plenty blurry when it's wide open.

Answer 6

http://en.wikipedia.org/wiki/Depth_of_field

Scroll down and look at the images of branches on the right side.

Very little difference between f2.8 and f4 which is only one stop.

You want to get as much distance between your subject and the background as possible, and you be as close to your subject as you can.

This will give you the best separation or out of focus background as possible for any f-stop.

I prefer the fixed aperture lenses, however, the difference in depth of field between f2.8 and f3.5 is effectively nothing.

Buy the best lenses you can afford. When you upgrade your camera, you want to use all the lenses you already have.

Answer 7

Go to www.pixel-peeper.com and you can check out hundreds of photos taken with different lens on different cameras...you pick and choose what you want to see. Have fun with your camera...the 50 1.8 really is a good deal to get started.

Answer 8

I would get a stabilized camera and get the zoom. then you dont need the faster lens.