My D5200 doesn't have built-in focus adjustment, so I get what I get with lenses. I've noticed with my 35mm 1.8G, sometimes it gets its focus off (front focus and backfocus issues both). This isn't a "thin DoF user error" (though sometimes it could be); it's definitely a problem. However, it's not *always* a problem, and I can't consistently figure out when I can rely on the lens. Usually in bright daylight, I can rely on the lens. Medium-lit situations (even if the shutter speed is good at 1/2000 at f1.8 with exposure compensation at 0 and ISO at 400 or so), the focus can be unreliable, especially at portrait focal lengths.

If I set my D5200 into Live-view mode (this switches the way the camera focuses, acts like a mirrorless camera, but the shutter lag between taking shots is tremendous), the focus is accurate and 100% reliable when there's no user error.

Does anyone have any advice on how I can still continue to reliably shoot at f1.8 without these problems (without using live-view mode)? My technique is correct, and I'd like to continue using my 35mm 1.8G for walk-arounds... but my 16-85mm VR is just far more reliable (in part I suppose any focus issues wouldn't be as apparent at its aperture range, but even so, its focus is dead on matched to my D5200, sharp as a tack in every shot I've taken correctly).

Beyond the synthetic tripod tests, are there other tests I can do? I'll post some test results when I have the time to do so this weekend (since I notice most people are at first apprehensive to trust a beginner's word).

The reason I'm starting to get frustrated is I went out and took some great shots of my girlfriend, and my zoom shots turned out great, but my 35mm shots (which would have turned out really well) ended up making the subject (my gf) blurry... all f1.8 - f2.2 shots. The shots were consistently out of focus, with her in the same position, and I know I refocused between each shot. I can't post pictures of her up here (she's beautiful but she wouldn't want pictures of her posted around, it's hard enough humoring her with the camera)... so I'll post test shots later to try to get some help.

This post was edited by Canadian_Man on Sep 5 2013 04:50pm

I'm almost certain this is user error.

Explain the process in detail when you are focusing/shooting portraits with the 35?

What focus points are you using? The very top and outer points will be hit and miss unless you are in a well lit or high contrasted scene. Are you focusing with the centre point then recomposing?

It would be helpful if you post a picture of her, just a small one, to see what you are trying to do. If it's out of focus then what's your beef?

I use the center focus point, I don't recompose, I focus on the eye or forehead, and then the face is out of focus. No recomposure is done, and my shutter speed is good and fast.

The difference in my most recent shots is about a 5-10cm backfocus. So she's still sharp if you view a small photo, but if you zoom just a little bit (not pixel peeping), she's clearly out of the primary focus area.

The lighting was favorable, and if I can't get shots in focus in good lighting (if I need glaring direct sunlight), then the lens is practically worthless to me >_<;

This post was edited by Canadian_Man on Sep 6 2013 03:18am

Your lens must be faulty if you are claiming 5-10cm of back focus. Back/front focus should only be a few mm, if that.

I still think it's user error.

Are you using a single point for focus or all of the points?

You shouldn't be focusing on the forehead as you need contrast to obtain accurate focus. Just stick with the eyes. If you are centre focusing you should try re composure but let's get to the bottom of this issue first.

I'm using single-point focus. That's all I ever use.

So are you holding the button half way then then fully depressing to take the picture?

Do you have an AF ON button ?

Hahahaha. Do you really think I'm that stupid?

How the hell do you think I've been using my camera? By not focusing ever and hoping it works? xD

This post was edited by Canadian_Man on Sep 6 2013 04:26am

err...

There are two ways to focus.. using the shutter button or by using an AF ON button.

I was asking if your camera had an AF ON button.

This post was edited by lithfkn on Sep 6 2013 05:15am

My camera does have a button which can serve as AF ON, but I have it set to exposure lock instead. I half-depress the shutter button to focus.

I've looked through a number of past photos, and realize that the lens is definitely not calibrated perfectly. I'm not sure what's exactly wrong, but my camera doesn't have built-in lens calibration I can often see that the focus ends up being a little off on the face/etc, even when I focus correctly on a target. This ends up giving me usually usable photos that can be printed, they can be sharpened and look great, and overall they're usable, but I still end up having a shot that is off-focus and I'm really not getting the sharpness I could be getting.

Hmmm... guess I'll do some actual test shots and post the raw files and all that. Does Nikon offer lens calibration under warranty?

This post was edited by Canadian_Man on Sep 6 2013 05:23am

AF ON for focus and exp is so much better, you should try it Using the shutter button as focus now feels so clunky.

Is the focus hunting? or does it stop on one point?