NX500 - Disappointed by AF performance

Dear All,

so far, I have been quite happy with my NX500. However, yesterday was my daughter's birthday and I actually felt let down a bit by the camera. While it often performed nicely as usual, I noticed four things which disappointed me:

1. AF performance with the 30mm is poor, often hunting, taking ages to find focus

2. I have set AF Release Priority to Focus - Shooting Speed Priority. So far this worked usually very good, but yesterday I had a lot of shots which were just completely out of focus. I don't know whether setting it to "Accuracy" would have helped, but such a poor performance is not acceptable no matter what setting...

3. I don't know whether it is the same as in (1.) and/or (2.) but I had (unavoidably) a lot of shots against light (my daughter blowing out the candles, in a well-lit room, but with a brighter window behind her). Although a green square was shown spot on the face of my daughter, a lot of images were either completely out of focus, or the focus was on something completely different (e.g. the cake topper) surely not in the AF square (and also not a brighter object).

4. In particular for shots of persons with a window in the background, the camera actually didn't take shots (with 30mm). It was hunting for finding AF, and then didn't find it and just gave up... My wife wanted to take pictures, and gave it back to me, frustrated, just saying that the camera doesn't take pictures... I didn't want to tell her that my new 600€ toy just needs a few more attempts (and 6 year olds at the dinner table are reluctant to constantly smile at you while the camera takes ages and several attempts to actually release the shutter...)

Luckily I took literally hundreds of shots, so that I have good images. But AF performance in these conditions (which were not really challenging or poor) is worse than with my old NX100.

Some information for clarification

- When I say blurred/out of focus, I'm not pixelpeeping. I refer to something were I (and my wife) immediately say "delete" when viewed full screen on a 14" laptop.

- I usually shoot in A mode, adjusting ISO (put on second wheel) to get a sufficiently short exposure time (usually at least 1/60s, often 1/100 or faster). I know the difference between motion blur and out-of-focus shots.

- Only today I realised that OIS 1 was on. But it shouldn't make that big a difference...

- Body firmware is 1.10. I haven't had the time to play in the newest one...

- Most problems appeared with the 30mm, but also with the 16-50mm PZ

- Drive mode was continuous normal

Sorry, I just had to get this out. As I said, I'm usually very happy with the camera, but not yesterday...

Best wishes,

Andre

Raw Jaw wrote:

andre95 wrote:

Strongly lit backgrounds always inhibit AF of any camera. The best is using Single Shot AF with a small box at center.

Well, I had the NX100 before for ~3 years. It never had such problems. I usually have a box of the size that the subject fully fills the box. I often have the box on the third-smallest size. With my way of framing, depending on distance and lens, the square nearly always covers the whole head, or a smaller area such as the eyes. My experience with using smaller squares is, that it then is more likely that the camera doesn't find focus (because it may happen that there are no big contrasts in the smaller square).

BTW, that the NX500 has a particular problem with focussing in backlit situations is known.

- I usually shoot in A mode, adjusting ISO (put on second wheel) to get a sufficiently short exposure time (usually at least 1/60s, often 1/100 or faster). I know the difference between motion blur and out-of-focus shots.

The minimum I shoot people at is 1/160, especially children being children.

That depends on the situation. If they are quietly sitting somewhere and there is poor lightening, it may be more effective to reduce shutter speed than to push ISO further... Sure, if they are running around I use completely different speeds...

- Only today I realised that OIS 1 was on. But it shouldn't make that big a difference...

- Body firmware is 1.10. I haven't had the time to play in the newest one...

Not good on your part.

True, but AFAIK there were no reports (and no claims in the Change Log) about noticably improved AF in the last minor update.

- Most problems appeared with the 30mm, but also with the 16-50mm PZ

- Drive mode was continuous normal

This was your big mistake.

Why? Showing a green square (= found focus) and then producing a totally unfocussed image should happen in no mode. And also that no focus is found at all shouldn't happen (at least not in these lightening conditions, they were indoors, but really not that bad - during a day in a function room with a lot of big windows and all ceiling lights on)

I suggest you download the user manual and read and apply its information. This will enable you to separate camera issues from operator issues.

I actually read the whole manual. I checked again, because I didn't remember anything about having poorer performance in Continuous normal [not High!]. That's the information of the handbook (exhaustive, there is not more):

[start citation]

Single AF: Single AF is appropriate for shooting a still subject. When you press [Shutter] halfway, the focus fixes in the focus area. The area turns green when the focus is achieved.

Continuous AF: While you press [Shutter] halfway, the camera continues to focus automatically. This mode is recommended for shooting action.

Notes: Depending on the type of lens, auto focus results may differ when you capture photos continuously using Continuous AF. Use an optional lens for smooth auto focus operation. Select an optional lenses from the following: - SAMSUNG 16-50mm F2-2.8 S ED OIS - SAMSUNG 16-50mm F3.5-5.6 Power Zoom ED OIS - NX 50-150mm F2.8 S ED OIS

[end citation]

Where does it say AF is worse? And it also says to use optional lenses for *smooth* AF operation. However, for just one shutter press, this isn't required?

Andre

zipcode wrote:

I only have the nx300, which is really bad in low light focusing, but I found that pressing the shutter immediately, so before the square gets green, usually results in poorly focused image, although the camera shutter doesn't trigger right away, it's still doing it after focus was 'found'. Also single square is usually worse than multi point. Not sure if these things apply to nx500, but they might.

Thanks for your input. Yes, I guess I often pressed the shutter in one go in the shots which did not work, not first half-way only. However, for moving subjects, this is usually what is recommended. Because if the subject moves, it will be out-of-focus between finding focus (half-press) and then the full-press. The same holds if you want to capture something which is fleeting and you have to be quick...

Andre

Raw Jaw wrote:

Thank goodness it was the camera and not you.

No need to be offended?

I consider myself a beginner, and don't know the technical details. You suggested that using Continuous AF was the big mistake, and that I should read the handbook. The handbook did not clarify why Cont AF performs so much worse (this, BTW, is just speculation, we don't know whether single-AF would have been the solution, but of course I'll try).

So, all I did was ask, and I do it again: Can you explain to me why Cont AF performs so much worse?

I mean, some scenes didn't change much overall (like blowing out the candles), but still a lot happened. So I just took one picture after the other. Approx. 30% are utter rubbish, i.e. focussed on something completely different than the AF-square or is totally blurred (see the attached example, before releasing the shutter, there was a green square just covering the face of the central child). The next two images focussed on the red box in the background (at least something), and the next image was nicely focussed on the face of the girl (the way I wanted it, and the way I would have thought because indicated by the green square on the face).

Honestly, how can I avoid this? I take a series of pictures under virtually identical conditions, and some shots go wrong by so much?

If I can do better, then I really want to. But for this I need to understand what went wrong.

Best wishes,

Andre

Hi Andre:

I have heard the 30mm is not the best performer when it comes to focusing. I am curious, did you happen to use Selection AF? What size was your focus point? Another option in that situation is to use manual focusing and focus peaking.

Raw Jaw wrote:

Thank goodness it was the camera and not you.

No need to be offended?

I consider myself a beginner, and don't know the technical details. You suggested that using Continuous AF was the big mistake, and that I should read the handbook. The handbook did not clarify why Cont AF performs so much worse (this, BTW, is just speculation, we don't know whether single-AF would have been the solution, but of course I'll try).

So, all I did was ask, and I do it again: Can you explain to me why Cont AF performs so much worse?

I mean, some scenes didn't change much overall (like blowing out the candles), but still a lot happened. So I just took one picture after the other. Approx. 30% are utter rubbish, i.e. focussed on something completely different than the AF-square or is totally blurred (see the attached example, before releasing the shutter, there was a green square just covering the face of the central child). The next two images focussed on the red box in the background (at least something), and the next image was nicely focussed on the face of the girl (the way I wanted it, and the way I would have thought because indicated by the green square on the face).

Honestly, how can I avoid this? I take a series of pictures under virtually identical conditions, and some shots go wrong by so much?

If I can do better, then I really want to. But for this I need to understand what went wrong.

Best wishes,

Andre

Would it not be easier to stop down, increase iso and focus manually? Especially where the subjects are remaining at a similar difference away from the camera.

This was the exact reason I returned the Sony A6000, Nex 7, Canon G7X. Even my Sony RX100III often misses focus too often at full tele, in full daylight.

Now I don't think I will consider the NX500. Bummer

Can anybody make a big sensor camera that can reliably GET THE SHOT?

I've been in this situation with the 30mm attached to my NX500.  I figured out the AF lamp doesn't activate consistently with a half press of the shutter in all low light conditions.  The auto focus starts searching which leads to poor results...

Guys, I'm new to the forum, but a long time lurker...

IIRC, with your settings, the camera used only phase detect auto focus, not contrast detect like your nx100 and my nx1000. AFAIK, you need Accuracy setting to use phase detect to get you very fast to probably the exact focus and then contrast detect kicks in to focus precisely. Why Samsung has issues with backlit subjects is beyond me, panasonic has only contrast detect and still they are able to track as good as PDAF in stills (video af on panasonic is on the other hand mostly useless).

I too am drawn to nx500, especially after helping parents of one kid video exactly the same situation with their nx500 (indoor birthday, candles like fireworks, stuff) with just kit lens at 16mm in 4k and I was amazed at images pulled from video (af was also spot on, but 8MP, f/3.5 and wide angle might have helped).

Will wait for next firmware update to see whether they will finally enable constant focus peaking...

I'm sorry to hear about your disappointment, and it's good that you are asking here. This image is certainly much worse than anything I've ever managed to "mis-produce" with the NX500 and the 30 mm, but the main reason for the misfocus are the dark subjects (the 30 AF is not great in low light anyway) in front of a strongly backlit scene. As it goes with such scenes, the cam tried to focus on the brightest spot, the window and curtains, but as it's too bright without sufficient contrast, it couldn't even find proper focus there.

This is a common problem with AF, in mirrorless cams especially, and Samsung's 30 mm lens in particular, and also the 50-200 mm. As your subjects are sitting and not really moving to and from the cam, half-pressing the shutter button until the AF square(s) are green before you press a way down, is recommended, and should yield better results, although focus may not be perfect still. Closing down the aperture would help, or using a different lens for such occasions, e.g. the 16 f2.4. Alternatively try the 12-24 if you don't mind increasing ISO. Or the fast 45 for portraits or even group shots if you have the space to move back. The 30 is really the worst of the lot in terms of AF speed and accuracy in backlit situations, as beautiful as it is otherwise.

You can also try different combinations of AF settings, but in my experience these don't make a whole lot of difference.

Andrea

I find that I get better performance with the NX500 and 30mm if I use the smallest size focus box and make sure subject is much larger than box. I always use AF selection..never let the camera decide.  I use AF speed priority. I also half press first and wait for box to go green before full press. I've been able to get in focus shots of kids biking with CAF most of the time.

Clive

telefunk wrote:

This was the exact reason I returned the Sony A6000, Nex 7, Canon G7X. Even my Sony RX100III often misses focus too often at full tele, in full daylight.

Now I don't think I will consider the NX500. Bummer

Can anybody make a big sensor camera that can reliably GET THE SHOT?

Big backlit window in the middle is not excusable - then do point the camera to another object at same distance. The problem is: The exposure adjusts to the bright background light during AF and the AF cannot see the other things. Maybe the Nx500 is a bit more problematic in this regard than the other NXes. Also, please no continuous AF except in a sports situation outdoors for what cont AF is meant for. Cont AF is not for people sitting on a table.

But there is one company who invented really something good regarding AF: Panasonic. I do not know if Panny masters this special scene, but if you search best-AF big sensor non-dslr cam, try Panasonic m43 newest camera or the LX100. Sensor is 20% smaller but that is what you have to accept.

On the other hand, mirrorless APS, here Samsung is comparably good. See the good situations for mirrorless AF: Touch-AF, face-detection; and on exposurewise easier scenes mirrorless AF is more exact than DSLRs. But maybe the Nx500 is not the best AF of NXes.

D300 never misses the shot

But seriously, I can't remember the last time I used it...

Thanks for all the helpful input, I'll try a lot of the suggestions you've

made.

Just to clarify a few things:

- "Cont normal" was the Drive mode, but the examples I have shown are single shots. They are not taken from a sequence of having pressed the shutter continuously. Press shutter, take 1 picture, release shutter. Wait briefly. Press shutter, take 1 pic, release, etc.

- I have set the AF to Selection AF. Mostly, I have the AF field pretty much in the middle. The size is the third-smallest. With smaller squares, I have athe situation of finding no focus even more often.

- I indeed may have often pressed the shutter fully in one go. However, in the German DSLR forum, a Canon guy with pretty much high-end equipment recently was wondering why his dog-shots were all not well focussed. They all recommended (and it turned that this was indeed the major problem), to press the shutter in one go, and *not* to press it halfway first. Kids are often moving at least a little bit, and with f2 this time delay may mean that e.g. the eyes are not in focus any more. I will experiment with it...

BTW, I shot true continuous shooting with the 50-200mm in a running game. AF and picture yield are fabulous (honestly, I'm still baffled).

Attached is another great example, this time outdoors. And no, I wasn't focussing on the finger The green square was roughly at the boxed out portion of the face (not my daughter, so anonymous). I know, it is backlit again, but still I find this poor...

Best wishes,

Andre