This might be a dumb question...

[Bubbles22]

I usually take pictures of just my family. Mostly my children so having my 35mm on or my 50mm and the aperture fairly low f /2.5 to 2 pretty low works for that. But when I want to take a pic of a groups say family at Easter I have a hard time knowing where to set my focus point and my aperture to get everyone's face in focus. I usually set the focus point on someone's eyes. My aperture is always set at f/2.5 or higher with this many people. This looks great on my lcd but when I bring it home on the computer I can see now everyone is 100% in focus.
What am I doing wrong?

 

[DiskoJoe]

Use a smaller aperture. Your depth of field is too shallow for mulitple people. Try f5.6 or f8 to start.

 

[Buckster]

This can help you get a good handle on it: Online Depth of Field Calculator

This post by Big Mike too: http://www.thephotoforum.com/forum/...ion-about-lenses-depth-field.html#post2567441

 

[Big Mike]

Do you have a smart phone? There's an App for that

App Store - Simple DoF Calculator
App Store - Simple DoF
DOF Calculator - Android app on AppBrain

 

[Bubbles22]

I had it smaller because we were inside and I didn't have my speed light on me. I hate the on camera flash. And my shutter speed was way to slow if I had it higher. Next time I will know just to bring it along. (I thought we would be outside more) I should have known better. At least I know that is my only issues.
So would you still use the 50mm? Another question is since I'm just a hobbyist I can't spend the kind of money on some of the other prime lens. Therefore, I have a 50mm f/1.8 and the 55-200mm f/ 4-5.6. If I were going somewhere with the family where lighting wasn't an issue say petting zoo, etc. should I just bring the 55-200 since I would start my aperture at 5.6 ish or would you bring the 50mm since it is known to take sharper pictures. I don't mind having to move to get the better shot.

 

[Bubbles22]

Note: If I have awful typing and spelling issues today I have a newborn and 19 month old at home and I'm trying to type really fast. Sorry, I know it is frustrating. But thank you for your responses it really helps me learn.

 

[Bubbles22]

This can help you get a good handle on it: Online Depth of Field Calculator

This post by Big Mike too: http://www.thephotoforum.com/forum/...ion-about-lenses-depth-field.html#post2567441

Thank you, I just bookmarked them!

 

[enzodm]

So would you still use the 50mm?

Not sure why this question: focal length does not matter. If 50mm is good for your composition, use it. But close aperture in order to have more depth of field.

should I just bring the 55-200 since I would start my aperture at 5.6 ish or would you bring the 50mm since it is known to take sharper pictures.

I would bring every lens that enters in your bag .
Typically I move with 18-55, one longer zoom among my two (50-150 or 55-250), plus one prime chosen among my old manual lenses (50 or 28 or 100 - it depends). This because my bag is somewhat small.
In your case focal lengths are overlapping, but sometimes you may need f/1.8 for shallow DoF.

 

[Big Mike]

I had it smaller because we were inside and I didn't have my speed light on me. I hate the on camera flash. And my shutter speed was way to slow if I had it higher. Next time I will know just to bring it along. (I thought we would be outside more) I should have known better. At least I know that is my only issues.

Exposure (photography) is always a 3-way compromise between shutter speed, aperture and ISO. So if you must use a smaller aperture to get enough DOF, but you don't want to drop your shutter speed, then you're other option is to increase the ISO. You will get more digital noise with a higher ISO, but it's almost always better than getting blur from a slow shutter speed or too shallow of a DOF.

Of course, the other option is to add light (flash or other) or just to find a location, situation that has more light.

 

[Bubbles22]

Big Mike, I understand the 3-way compromise. (This might be the only thing I understand) I just may have wrote it wrong on here. I was saying I forgot my speed light, that is why I made my aperture smaller. And I did move my ISO up to 400 but I have a D3100 so I hate to go past that. There just wasn't enough light but I wanted to make sure that I wasn't doing something else wrong. So next time I will make sure to increase my aperture a bit and not forget my sb-800 at home.

 

[Big Mike]

Big Mike, I understand the 3-way compromise. (This might be the only thing I understand) I just may have wrote it wrong on here. I was saying I forgot my speed light, that is why I made my aperture smaller. And I did move my ISO up to 400 but I have a D3100 so I hate to go past that. There just wasn't enough light but I wanted to make sure that I wasn't doing something else wrong. So next time I will make sure to increase my aperture a bit and not forget my sb-800 at home.

In my class, I teach my students not to fall victim to the 'ISO Bias'....and that's exactly what you are doing.

You didn't want to move the ISO higher than 400, so you ended up using too large of an aperture (getting too shallow a DOF).
I'd be very confident that your camera can easily give you very good results at ISO 800 and even 1600....maybe higher with some noise reduction applied in post.

If you have been finding that you do get too much noise at ISO 800, then I'd first want to know how accurate your initial exposures are. If you get good exposure 'in-camera', then ISO 800 should be just fine. But if you underexpose and have to brighten the images in post...then ISO 400 may not be low enough. If you nail your exposure or even go a little brighter (Expose to the Right) then ISO 1600 would like be acceptable.

Secondly, I'd want to know how you are evaluating your noise levels to determine how much is too much. If you zoom into 300%, you are going to see flaws every time.
You should evaluate noise levels at around 100% zoom and also know that a little noise reduction can go a long way.
Lastly, if you print an image...much of the noise will be erased by the act of spraying ink onto paper.
Lastly (again)...even if you print a large image that has some noise...you have to keep in mind that large prints are meant to be viewed from farther away...and at that point, the viewer won't see the noise anyway.

Long story - short.....don't be so afraid to raise your ISO.

 

[Bubbles22]

Secondly, I'd want to know how you are evaluating your noise levels to determine how much is too much. If you zoom into 300%, you are going to see flaws every time.
You should evaluate noise levels at around 100% zoom and also know that a little noise reduction can go a long way.
Lastly, if you print an image...much of the noise will be erased by the act of spraying ink onto paper.
Lastly (again)...even if you print a large image that has some noise...you have to keep in mind that large prints are meant to be viewed from farther away...and at that point, the viewer won't see the noise anyway.

Long story - short.....don't be so afraid to raise your ISO.

I think this might be my problem! I didn't know the 100% rule. I wish there was some good classes near me. But the last class I went to wanted to focus on the things I had already been taught or had taught myself by the books people have recommended. Not to mention they then had to teach others how to start to shoot in manual so I didn't get much out of it. Like I said in another post. There are so many things to learn and some of the simplest things go along way.

 

[STM]

Frankly, I am at a loss as to why this has disappeared from so many lens barrels.....depth of field scales!

In your case Bubbles, the best thing to do is to focus on a centrally located (front to back) person in the group and then focus on them. You then use an appropriate aperture, using those DoF scales to include everyone in front and back of them, based an estimation on your part as to how far in front and behind they were from your focused subject.

 

[greybeard]

Try doing what you are doing, only using f/8 instead. Should work fine.