50mm f1.8 usage?

[Anewman]

Great shots, what camera do you use?

Thanks.

I shoot with the now obsolete Canon 20D.

 

[PoohJen]

since i don't yet get what the 1.8 does (or rather, how to manage that part of dslr-land), what can this lens do that my Sigma 18-125 can't/doesn't?

Thanks!

 

[jann1033]

since i don't yet get what the 1.8 does (or rather, how to manage that part of dslr-land), what can this lens do that my Sigma 18-125 can't/doesn't?

Thanks!

i might be able to give an example...i was taking a tiny partially frozen snowy waterfall that is in a little ravine today( low light) and my 28-135 ( f3.5-6.3) would only let me get a faster shutter speed ( over 250) to freeze the water when i used a high iso( think it was 800) the 50mm 1.8 i could get all the way up to 1600 shutter speed f 1.8 at 200 iso so less noise and froze the water. as it ended up i liked the slower speed( really slow like 30) better but at least the 50mm gave me a better option than the other lens. cause the aperture on the 50 can get a bigger hole, it needs less light and so you can get a faster shutter speed

 

[Gdad]

since i don't yet get what the 1.8 does (or rather, how to manage that part of dslr-land), what can this lens do that my Sigma 18-125 can't/doesn't?

Thanks!

Wide open at f1.8 this will give you an exceptionally shallow dof-

 

[PoohJen]

i might be able to give an example...i was taking a tiny partially frozen snowy waterfall that is in a little ravine today and my 28-135 ( f3.5-6.3) would only let me get a fast ( over 250) to blur the water when i used a high iso( think it was 800) the 50mm 1.8 i could get all the way up to 1600 shutter speed f 1.8 at 200 iso so less noise and blurred the water. as it ended up i liked the slower speed( really slow like 30) better but at least the 50mm gave me a better option than the other lens. cause the aperture on the 50 can get a bigger hole, it needs less light and so you can get a faster shutter speed

ok, so the 1.8 is the aperture (which i still can't figure out how to adjust on the XT, so i just always bump up ISO. just a matter of reading up on it AHEAD of time, I guess!)

not sure what 250 and 1600 (if not ISO) mean, but it's late. go to bed, Janet! I'll check back in the morning. Also, it was too dang cold to go out with the camera today; I commend you! I spent the day playing inside w/ my trial PE5 download.

eta: cool pic Jeff!

 

[Anewman]

since i don't yet get what the 1.8 does (or rather, how to manage that part of dslr-land), what can this lens do that my Sigma 18-125 can't/doesn't?

Thanks!

Well the Sigma can not open up to F/1.8
@50mm I expect the max aperture on the sigma to be around F4.0

What does that mean?
Larger aperture equals more light allowed into the chamber, which can mean the ability to use faster shutter speeds or lower ISO. (remember smaller number equals larger opening)

Say you are shooting indoor Volleyball @ ISO 1600... where the Sigma might give you a shutter speed of 1/200th most images will be blurry unless the subject is standing still, The 50mm 1.8 might allow a shutter speed of 1/800th which should cancel out most movement blur.

 

[Miss Kelly]

I have the 50mm lens and love it most of the time. I do have some focusing issues but that may be due to user error. I'm looking for an additional lens though. I think I need one for studio shots. I feel like I have to stand/sit/lay way back in order to get a good shot.

 

[jann1033]

ok, so the 1.8 is the aperture (which i still can't figure out how to adjust on the XT, so i just always bump up ISO. just a matter of reading up on it AHEAD of time, I guess!)

not sure what 250 and 1600 (if not ISO) mean, but it's late. go to bed, Janet! I'll check back in the morning. Also, it was too dang cold to go out with the camera today; I commend you! I spent the day playing inside w/ my trial PE5 download.

eta: cool pic Jeff!

to change the aperture use the creative mode on "av", then turn the black dial (thumb dial on the top by the shutter button)...you'll see the number closest to the little exposure chart change ( the second number from the left in other words in the viewfinder.,) that will tell you what ever aperture setting you are using .( i think you can also change it by a little av button on the back but i can never get that to work so i just use the av dial if i want a particular f stop)but is also determined by your lens...for example if your lens is f 3.5, it would not be able to open the hole of the shutter( the aperture) enough to be f1.8 ... which is where the 50mmf1.8 comes in, it allows for a bigger hole so lets in more light.... the shutter speeds, like 250 and 1600 would be the fraction of a second the shutter will be open at what ever setting you set it all ie 1/250 of a second , 1/1600 of a second etc etc etc

i'll be up for hours more,,,my insommnia has kicked up...hopefully i will sleep sometime tonight

for some reason my white balance that i set for snow is still turning out blue and i forgot to reset it so if i get around to fixing the pics i try to post the difference

 

[handicap18]

jann, try using auto white balance for snow pics then using a +1 exposure compensation. The camera doesn't know you want it white, not gray.

PoohJen, aperture (aka f/stop) is basically the same thing as the pupils on your eye. When you walk into a dark room your pupils dialate (open very wide to allow as much light in as possible). When you walk outside in a bright sunny day they close very small because there is to much light. On a camera lens, either the camera makes these changes or you make them by adjusting the f/numbers. Not all lenses have the same capabilities. Your Sigma lens has limitations on how big the aperture can open up. 18-125mm f/3.5-5.6 means that at 18mm the widest the aperture will open is to f/3.5. At 125mm the widest the aperture will open is to f/5.6 which is smaller than f/3.5. As you get closer to 125mm the size the apeture on the lens will open will be smaller and smaller. Its part of the limitation of most zoom lenses. This is why some zoom lenses are cheep and others are very expensive. The expensive ones most likely have a constant small aperture though the entire zoom range. IE: 70-200mm f/2.8. No matter what focal lenght the lens is at it's aperture will open to f/2.8 (which is bigger than the f/3.5 on your current lens). This is also a very big (physically) and expensive lens because of this.

The 50mm f/1.8 is used by a lot of photographers, especially amertures, because of its ability to have its aperture open very wide and its low cost. 50mm in film speek is considered to be the basic lens as it is very close to what the human eye sees. Though in digital speek its actually longer because of the crop factor.

To compare your lens at the 50mm length to the 50mm f/1.8: Using ISO 1600 with your current lens in a room full of windows late in the day as the sun is setting, no house lights on, your widest at that length might be around f/4 or so which would give you a shutter speed of around 1/40th. With the 50mm f/1.8 in the same light at the f/1.8 aperture your shutter speed would be around 1/125th. Thats definately a big difference. Also the 50mm f/1.8 is very sharp around f/5.6-f/8. Your current lens at 50mm at the same f/stops wont be as sharp.

I hope this info helps. I kind of rambled a bit there, I hope I didn't confuse you.

 

[jann1033]

jann, try using auto white balance for snow pics then using a +1 exposure compensation. The camera doesn't know you want it white, not gray.

....

changed this quote so it's all about me
actually i set my custom white balance for snow but even set on that it is still "blueish" just not as "blue ish"( not sure if they all work the same but you took a picture of the snow( clean no yellow snow allowed) then entered that into white balance ) and it is better with some lenses but with my canon lenses is still blueish...i was thinking maybe it's the lens so i figured i try again with the most blue one and see how that works but now it's melting so no white white snow, just mucky brownish gray snow so i'll have to wait

 

[Snurk71]

Just when I think I get aperature, f-stops, shuuter speed, DOF...

I get the advantage of the 50mm f1.8 in that I can get a brighter exposure than the sigma 18-125 at the same shutter speed (because the max aperature on the sigma at 50mm would be around 4.0 compared to 1.8). I get that I won't have a very deep DOF at that low of an aperature (low aperature number = shallower DOF). And I think I even get that the picture will be "better" because the 50mm is a better lens (I'm not really understanding why, but I'll take the experts word for it).

But there are a few things I still might not be getting yet.

1) When you say the 50mm is a "faster lens", is the lens actually mechanically faster or is that shorthand because it *can* be faster (you can shoot with a faster shutter because of the wider aperature, assuming everything else is the same)?

2) I assume you can increase the aperature above 1.8, getting a deeper DOF?

3) Do you manual or auto focus with a prime lens like this, since it sounds like you don't have a lot of room for error if the autofocus grabs the wrong thing?

Thanks

 

[handicap18]

Just when I think I get aperature, f-stops, shuuter speed, DOF...

I get the advantage of the 50mm f1.8 in that I can get a brighter exposure than the sigma 18-125 at the same shutter speed (because the max aperature on the sigma at 50mm would be around 4.0 compared to 1.8). I get that I won't have a very deep DOF at that low of an aperature (low aperature number = shallower DOF). And I think I even get that the picture will be "better" because the 50mm is a better lens (I'm not really understanding why, but I'll take the experts word for it).

But there are a few things I still might not be getting yet.

1) When you say the 50mm is a "faster lens", is the lens actually mechanically faster or is that shorthand because it *can* be faster (you can shoot with a faster shutter because of the wider aperature, assuming everything else is the same)?

2) I assume you can increase the aperature above 1.8, getting a deeper DOF?

3) Do you manual or auto focus with a prime lens like this, since it sounds like you don't have a lot of room for error if the autofocus grabs the wrong thing?

Thanks

When people refer to a lens as fast it means it has a wide aperture (ie: f/1.8, f/2.8 even f/4), thus allowing for faster shutter speeds. At the wide apertures, they will generally focus faster than other lenses because the lens allows more available light.

My 50mm f/1.8 goes down to f/22 I think it is, maybe f/29, so yes, you can increase to get a greater DOF

There are both AF and Manual focus 50mm f/1.8 lenses. With Nikon I believe it is an AI-S lens for manual and AF for auto focus. Manual focus lenses are less expensive. Where you don't have a lot of room for focus error is when you open the lens wide, ie: f/1.8 f/2 etc... That is where your camera's 5, 7, 9 or 11 point auto focus system comes into play. You can put your subject where you want it, then adjust your auto focus point, or you can center your subject with the center focus point then use the AE/AF (auto exposure/auto focus) Lock button and move the camera to the composition you want.

 

[jann1033]

the $70 ish canon is auto focus...personally it's not a big problem usually, the only time i had a problem was when i wanted to take 2 people in a line, i thought i focused on a closer subjects , but someone behind them was in focus . usually i only have one of my focus point lit up and i think i might have been slightly off center with it ( it focused right past the people i wanted and focused on someone between their heads ) unfortunately i can't always see all that well or maybe i would have noticed pre shot i don't know. by locking the focus first i may have been ok but i neglected to do so...(it was my first time using my camera and this lens in this situation and i was as usual a nervous wreck about it... like who really cares except me )

 

[Ratpack]

Just picked up Nikon's version of this lens and below is my first attempt at using it. I still have a little to learn about it, but I can already tell it will be one of my favorites. The boy kept moving back a little so he got a little out of focus, so I probably should have increased the f-stop, but not bad for my first trial I think.

 

[Gdad]

Just picked up Nikon's version of this lens and below is my first attempt at using it. I still have a little to learn about it, but I can already tell it will be one of my favorites. The boy kept moving back a little so he got a little out of focus, so I probably should have increased the f-stop, but not bad for my first trial I think.

Yery nice- wide open at f1.8 is tuff for portraits (especially moving kids- trust me I know). The dof is so shallow sometimes one eye is sharp and the other is not. Closing it 1 or 2 f stops still gives you a nice shallow dof for backgrounds, etc. but not quite as extreme.

 

[Anewman]

Just picked up Nikon's version of this lens and below is my first attempt at using it. I still have a little to learn about it, but I can already tell it will be one of my favorites. The boy kept moving back a little so he got a little out of focus, so I probably should have increased the f-stop, but not bad for my first trial I think.

Nice shot, I notice you did not use flash. Sometimes I take one with available light, and then I try the exact same settings with some fill flash.

Camera model: NIKON D50
Date/Time: 2006:12:12 20:25:29
Flash used: No
Focal length: 50.0mm (35mm equivalent: 75mm)
Exposure time: 0.100 s (1/10)
Aperture: f/1.8
Whitebalance: Auto
Metering Mode: center weight
Exposure: Manual
Exposure Mode: Auto bracketing

 

[Ratpack]

Thanks so much for the comments and advice. I still need to play with this lens some more so that I will know kind of what to expect at different settings. I would have liked to played a little more during this shoot, but the kids had had enough after about 5 minutes, so we took the best one we had. Next year's will be much better I promise.

 

[senecabeach]

Gdad...Ratpack..

"Wonderful" picture of your lil' ones !!