struggling with my 50mm 1.8 D on nikon D3100

i use my nikon D3100 wit a 50mm 1.8D.

i really seem to struggle with the manual focus to get sharp images. the image looks sharply focused in the viewfinder, but somehow the results are not the same.

in low light , i would prob end up taking 20 shots before i settle for one. i hate using the live view, but that seems to be one way to get proper images.

any clues what i am doing wrong??

Open up the aperture/increase the ISO setting, so that you use a faster shutter speed.

rriveros said:

Open up the aperture/increase the ISO setting, so that you use a faster shutter speed.

Click to expand...

A larger f-stop value (smaller aperture) will give you a deeper DOF which will make it easier to hit focus.

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See my plan (in my profile) for what I shoot with. See my gallery for images I find amusing.

You are not doing anything wrong. The key is your problem is your need for taking pics "in low light"

stopping down to get a wider DOF will force you to get even worse ISO's.

This is the curse of the motorless bodies by Nikon. Personally I would have snatched up these cheap bodies for a backup cam, but being forced to manual focus my f1.8 lenses is a deal breaker. The only real solution is to get a lens that will auto focus on your camera. The 35/1.8 comes to mind. The fantastic bargain that is the 50/1.8 simply isn't a bargain anymore once you have to manual focus it. I sort of moved up to DSLR because of this lens (on a D50 that was the last cheap body that COULD AF it). Then I added other AF lenses none of which can auto focus on the cheap bodies.

My D50 is still a backup body to my D700, sad to say. In your case, either consider getting more expensive lenses, or getting the cheapest body you can afford to AF on lenses you might want.

I still shake my head at these bodies. To get a backup body it appears that I'll have to pay over 1000 dollars to get that stupid AF motor in a "cheap" cam again. And suggestions to a use like you sound stupid since solving your problem can involve a lot of money on either lenses or a new camera. Or forget manual focus and use your consumer lens with flash.

Guy Moscoso

jassli said:

i use my nikon D3100 wit a 50mm 1.8D.

i really seem to struggle with the manual focus to get sharp images. the image looks sharply focused in the viewfinder, but somehow the results are not the same.

in low light , i would prob end up taking 20 shots before i settle for one. i hate using the live view, but that seems to be one way to get proper images.

any clues what i am doing wrong??

Click to expand...

Easiest solution would be to sell your 50mm and replace it with either the 35mm F/1.8 AF-S or the new 50mm F/1.8 AF-S

Sounds to me like a little technique improvement is in order. Of course I could be wrong and it might be an equipment issue but let's explore a little technique, shall we?

The hint I take from your "low light" comment is we are dealing with slow shutter speeds. I know everybody thinks they are rock solid when taking a shot but that's not the case about 99% of the time -- maybe more. Set you cam so the shutter will not trip (probably turn it off), look through the viewfinder at a stationary target. and push the shutter release with your normal force as if taking a shot. Did the target "move"? Probably so, huh! That slight amount of movement most often results in a blurry image. Practice until you can apply a shutter release that causes no or minimal movement. Now, set your cam in multi-exposure mode and take a 3 or 4 series of shots at a stationary target. Was the 2nd or 3rd image in the series the sharpest? If so, that shutter trip of your trigger finger is the culprit.

Now, to confirm, take some shots from a solid tripod. Are they sharper than your hand-held images. Probably so, huh. Any speed much slower than 1/60th handheld is going to give you a blurry image unless you are very accomplished at being steady.

One little equipment note: the 50/1.8 is not known to be particularly sharp when shot wide open at F1.8.

Try the techniques mentioned above to see if they help a little. Let us know how it works out for you. Good luck!

Phil

Jon Rty said:

Easiest solution would be to sell your 50mm and replace it with either the 35mm F/1.8 AF-S or the new 50mm F/1.8 AF-S

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I agree totally. You are wasting your time with that lens if you cannot use auto focus. That lens was not made to focus manually like some other lenses. Sell it. Get the 35mm F1.8 or the new 50mm AFS. I've been thru that already. Sell it.

It's darn near impossible, I practiced with a tape measure on the table next to a focusing object (a sweater or towel wadded up) to get better feedback and only with lots of that did I get my hit rate up to 1 in 7 or so. I haven't tried a split prism viewfinder, but that's probably my next step.

"any clues what i am doing wrong??"

Does the D3100 have focus indicators (ARROWS) in viewfinder? (The D700 does -- and it tells you if you need to turn left or right before the subject is in focus. These arrows are so accurate that they are FAR more accurate my own eye.) My eye gets tricked so much. Manual is not easy. Its a skill where you learn your lens, you learn your camera over the course of a year until you memorize how things look through the lens when in focus. Its not easy -- at all. And slim focus areas (1.4 / 1.8 / 2) don't make it any easier. Manual focus is a lot easier at f/2.8 and above (preferably f/4, 5.6, or 8).

If your has those arrows -- use them!

After that, put in your order for the 50/1.8AFS-G NOW. Becuase this problem isn't going to go away. Just get the 50/1.8G for 100$ more. Done deal.

Later get a 35/1.8G when you have the chance.

Good luck!

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Sincerely,

GlobalGuyUSA

I had a brief read through some of the comments here and would like to throw in my two cents. Don't be distracted by autofocus, you don't need it and never will need it if you can master a few basic principles of photography. It took me a while to wrap my head around it, but I often see my camera as an extension of my body. Have you ever tried shooting without looking through the viewfinder? That 50mm F1.8 lens is a great piece of machinery. Take note of those little numbers on the lens, the ones that measure the distance in meters and feet. I shoot primarily by those numbers. For example, if I rotate the focus ring on my lens to "1", I understand that anything that is 1 meter away from me will be in focus. There should be a little mark on top of your camera, it often looks like a little circle with a line through it. That icon actually marks the starting point from where the 1 meter begins. So, try this as a fun experiment, you can even use a meter stick if you're not sure. Place an object in front of your camera at 1 meter distance. Rotate the focal ring on your camera to "1" and place it 1 meter away from the object. Don't look through the viewfinder, just aim the camera at the object and shoot. It worked, right?

Once you do that for a while, you will get used to judging space with your eyes, and like me and many other photographers who love prime lenses, will start getting very sharp photos at shallow depths of field by referencing those numbers. I do a lot of street photography and prior to going out, I'll decide the distance first, rotate the focal ring to the number I want, like "2" for 2 meters, then I'll just start walking and shooting from the hip. I love the shallow depth of field you can achieve with prime lenses, and shooting in low light is a blast. Never be afraid to push your camera to the limits either if you need an extra boost in low light, Nikon does great noise reduction and I bet you D3100 can handle ISO 3200 and 6400 without breaking much of a sweat. I like the grain it gets, it gives it nice character.

Jonathan Siegel said:

. . . Don't be distracted by autofocus, you don't need it and never will need it if you can master a few basic principles of photography. It took me a while to wrap my head around it, but I often see my camera as an extension of my body. Have you ever tried shooting without looking through the viewfinder?

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Very Zen. I mean that in a good way.

But . . . a couple of things. You don't give much information on how you have your camera set up so to be explicit:

Set the lens to manual focus.

Set the camera to either A or S mode (aperature or shutter priority). In low light you might want to use S mode around 1/60 which is just pushing it for hand held with good technique (1/100 is considered about average for controlling camera shake with a 50mm lens on DX)

Set the camera to Auto Focus Area Mode Single Area AF - this means that the camera uses a single point to detect focus.

Make sure the single point is in the middle and lock it there

Set the camera to Single servo AF (AF-S). This means that the camera locks focus when you press the shutter half way.

When you look through the viewfinder, watch the Auto Focus indicator which is the dot on the bottom left of the viewfinder:
http://www.imaging-resource.com/PRODS/D3100/D3100VIEWFINDER.HTM

The camera is still detecting focus, but because it doesn't work without a motor in the lens, it can't turn the focus ring on the lens - so you have to.

Press the shutter half way and as you turn the focus ring the dot will light when the camera is in focus on the single point.

The 50 1.8 is a great lens for the price. Wide open (at 1.8) it has a razor thin depth of field - really shallow so that on a head and shoulder portrait, if you are spot on focus of someone's eye, the eyebrow may be out of focus, and if you sway a little bit (don't hold the camera rock-solid-tripod steady) the focus plane isn't going to be where you want it at all. Stopping down improve the depth of field but means in low light you need to lower the shutter speed and camera movement and subject movement start to become problematic for maintaining sharpness.

Does that help and/or make sense?

jassli said:

any clues what i am doing wrong??

Click to expand...

Could very well be the mirror in your viewfinder needs adjustment.

The mirror on a D70 I had was wildly out of specs and made any sort of MF impossible!

Mounting a split screen is useless if the mirror isn't OK, as found out.

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Phil_L

Hahaha, thanks, I do take a sort of spiritual approach to my photography. You're right though, I should have given a bit more detail but you got it with your post. I usually shoot either full manual or aperture priority. I go full manual when the sun sets and usually stick to aperture priority during daylight since I find it sort of a hassle to keep adjusting it when I walk through shadows, etc.. Since I shoot more at night, I often leave the lens wide open, so in this case F1.8, ISO1000+, and a shutter speed no slower than an 80th of a second. I use spot metering with a single focal point, although I never use the focal points. Good point though, when I first got rolling with manual lenses I used the green dot quite a lot to get the hang of it. Once you've used that green dot for a while, you'll also start to get a good feel for distance/depth. Just keep at it with that lens, the 50mm F1.8 is often referred to as Nikon's absolute sharpest 50mm lens, it's a classic.

Have you adjusted the diopter to account for your vision? There is a small little dial to the right of the viewfinder to make adjustments. ( http://my.safaribooksonline.com/book/-/9781435459403/nikon-d3100-roadmap/42 )

If you have a lens that autofocuses; when that one locks focus, does the image in the viewfinder appear sharp?

jassli said:

the image looks sharply focused in the viewfinder, but somehow the results are not the same.

Click to expand...

It sounds like you should stick with AFS lenses on that body. Get a 35mm f1.8 or the new 50mm f1.8 AFS. Personally I prefer 35mm on DX and 50mm on FX.

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http://www.andrewsandersphotography.co.uk

I take it you are using the rangefinder function? The rangefinder has never failed me on my D3100, focusing at 85mm.

A questions for you:

• Are your images sharp at some point, just not where you thought you focused? Or are they out of focus all over?

If there is not some point that is in focus, that points to technique (vibration when you trip the shutter; long exposure times that you can't hand hold; etc.).

If your pictures are sharp, just not at the correct place in the picture, that points to missing the focus point. Could be the lens back/front focusing, or just missing the correct focus point with the very shallow DOF when the lens is wide open.

Posting some pictures would help.
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Dave from OH

Manual focus is a skill like anything else, but I think it's difficult to do with inexpensive AF lenses not really designed for the purpose, i.e. thin focus ring not optimally located.
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Lora
Profile is wrong, I've been on Dpreview since June 2006.

As others said. Do not let the shutter speed below 1/60, keep an eye on the focus confirmation dot and practice.

Some of my favorite portraits were made with the 50 1.8 (on a D40 that is probably less demanding). The combo has the advantage of fitting in a large pocket

Moving targets are still pure luck.