Am I expecting too much from a wide angle lens?

I just got the Tamron 17-50mm 2.8 today that everyone raves about. I don't get

it, I don't see any improvement over my 18-70mm in sharpness, contrast, etc.

Other than the 2.8 benefit, I don't get it.

 

My 55-200 VR is awesome, it focus' just where I want it to, no issues at all.

 

Am I expecting the wide angle to be more precise than it's capable of?

Here's some examples:

 

 

This one is OK but I can't get it to focus on the exact spot I want it to.

 

<a href="

src="http://farm2.static.flickr.com/1131/641568359_3fc0186581.jpg" width="500"

height="334" alt="outside1.jpg" /></a>

 

 

This is a perfect example, focus is way off, it should be on him, his eyes, not

the railing in front of him.

<a href="

src="http://farm2.static.flickr.com/1306/642448334_0ee0e0ee1b.jpg" width="500"

height="334" alt="outside2.jpg" /></a>

 

 

This is more what I'm looking for (a bit of tweaking with this one, no

sharpening though, just increased blacks, contrast on iris and obvious border

& text) - taken with my 55-200 VR. I focused on her eyes and that's what I got:

<a href="

src="http://farm2.static.flickr.com/1078/605929834_f1547afd54.jpg" width="476"

height="500" alt="Sams icecream cone.jpg" /></a>

 

 

So, am I not going to get what I'm looking for in a wide angle. Is the focal

plane too big to be that exact?

 

The top two were shot in RAW, aperture mode, AF-S. I locked shutter by pressing

1/2 way, composed and shot (what I always do). These were taken late afternoon

and the only way to get them at at least 1/50ss was to shot at 2.8 - hence the

reason I bought this lens.

 

Would the 18-200 VR serve me better with the VR abilities rather than the 2.8?

I'm very frustrated that I can't take a decent pic of my kid at 5pm in the

middle of the summer and not have it in focus.

 

TIA

Where did you put which active focusing sensor?

 

That is the hitch here!

Even though you say you are focusing on his eyes and recomposing - it is obvious that the camera is focusing on the fence rather than your son's eyes.

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Make sure that you are in the "single area focus" mode.

VR is only good for stationery objects so it really depends what you are shooting.

 

As far as your lens goes, I have the Nikon 17-55 2.8 and find my 18-55 gives equivalent pictures with good lighting or with flash. A 2.8 lens has advantages over a 4-5.6 lens, but usually the advantages are more apparant when the lighting conditions are poor or if you need a small depth of field.

 

I have no experience with your lens but I have read here of others commenting about focussing issues with non-Nikon lenses. Since you just got it, it has a warranty - you may need to use it.

 

Here is a tip - try shooting with a flash in the late afternoon and see if you like the results.

Just reinforcing what Elliot has posted:

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Using the flash in bright sunlight is a very good idea. It helps to eliminate harsh shadows on a person's face as well as adding a definite sparkle to their eyes.

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We always use a flash on our outdoor wedding shots just for those reasons and the results are much better than without the flash.

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Here is an example: <a href=http://www.almariphoto.net/sisters1.html>Bride with two bridesmaids</a>

It would be nice to have some exif data for these.

 

At 17mm, f2.8, with a distance of 10feet from the focal point of the lens to your subject, the depth of field will be between 6.25 and 24.5 feet. That doesn't seem to match picture 2 above, of course I'm just guessing at the distance and focal length used. But with a 17mm focal length you should have plenty of depth of field so that focus accuracy is not that big of an issue

 

At 70mm, f2.8, with a distance of 15feet the depth of field will be between 14.3 and 15.8 feet.

 

You might want to test your new lens for focus accuracy; maybe you got a bad example.

Thanks all. I was trying to avoid flash, hence the 2.8. For exif data, click on the image, it'll take you to the flickr page, on the right, click on more properties - you'll get more info than you could want.

 

In a nutshell:

#1 1/60, 2.8, ISO 100 - new Tamron

#2 1/50 2.8 ISO 100 - new Tamron

#3 1/125 F5, ISO 160 - this is with my Nikon 55-200mm VR

 

My active focus sensor was in the middle - it always is. If I want to recompose, I'll hold the shutter 1/2 way and recompose. It's also always on single focus area. I like to have the control.

I believe you are using a D50, right? I would start exploring all 5 AF points. Typically, I would use the top AF point, in either the portrait or landscape orientation, when photographing a child.

 

Using a camera with 11 AF points, I tend to use the top AF point on either the left side or the right side.

Camera shake introduced by hand-holding is the great leveler of lens performance. You can see, at a glance, just how effective the VR is in this respect. As a rule of thumb, use a speed 3x faster than predicted by the focal-length rule, and be sure to include the cropping factor in that calculation. On that basis, an 18mm lens would require a shutter speed of 1/90 second to produce consistently sharp images.

 

Secondly, most lenses tend to be relatively soft at the maximum aperture - some more than others. Nikon lenses, even inexpensive ones, tend to perform well at all apertures and zoom ranges. Tamron and other third-party lenses are inconsistent in this regard. There a few gems and a lot of dogs, and build quality definitely suffers compared to Nikon.

 

"Focus and recompose" has a couple of pitfalls. first, you must be sure the focus locks in, and is not set to the "continuous" mode. Secondly, the plane of focus is parallel to the film plane, and turns when you recompose. At wide apertures, this will put the object you wish to be in focus behind or in front of the plane of sharpest focus.

Thanks Edward. I always shoot in AF-S (I mentioned that in my OP). I've read that using the other focal points can be less sharp than the center point, and that's why I tend to recompose. I'm also trying to catch a moment (although the 2 above are in no means special moments) so it's quicker for me to lock focus and recompose than to move the focal point around.

 

I've never read to use a shutter speed 3x as long as your length. I've always read at least as long, so at say 50mm, I'd use 1/60 or faster.

 

Forgot to say that I have a D80.

Try using the closest object focus mode. My D200 has it. D80, I don`t know. Selection lever on the back.

 

Can you tell if it is missing focus looking through the finder? I probably would have used the big superman logo for a focus point. Cameras like large high contrast targets.

The effect of camera shake at exactly the "focal length reciprocal" rule is comparable to the circle of confusion used for depth of field calculations. Some people are steadier than others, some have better technique, but nobody is steady all the time.

 

Whenever possible, you should use a tripod. I realize that's neither practical nor desirable with children or action in general, but a good practice for landscapes and making comparisons. It is educational to see what a dramatic effect a tripod (and good technique) has on sharpness.

 

I suggest using ISO 400 for hand-held shooting outdoors. This is a compromise between grain/noise and shutter speed to overcome camera shake. You also get much better range from fill-flash at higher ISO, provided the shutter speed is below the sync maximum.

 

The main difference between focus spots is that some are more sensitive to vertical (or horizontal) detail (e.g., stripes and edges), and others (especially the center spot) work with any orientation. This is more an issue about acquisition than accuracy. If the lens pops into focus when using any given spot, it is working correctly and will produce sharp focus.

 

The shifting plane of focus is an issue when the angle you turn to recompose is large, as when working close to the subject. The further you are away and the longer the focal length, the less the effect.

Edward - thank you for all your great info. I've decided to return the Tamron and work a little harder with my 18-70mm Nikon lens. It seems the quality between the two are comparable from the many samples I've viewed online and the few I shot yesterday (I did many more than posted, more close ups and landscapes). I think the Nikon takes better landscape photos from what I've looked at and experienced in the past year. I also have a 50mm 1.8 I can try again and work with above.

 

Looks like I need to work more on my technique and less on needing a new lens. The 2.8 won't give me the focus I want, but working with ISO (hate going to high and dealing with noise, but noise ninja does a decent job) and fill flash. I do have a great tripod that I use for macro work but not for outdoors in the casual environment I'm in with my family.

Carolyn, since you now have a D80, it is even better. I would highly recommend using the "corner" AF points for photographing children; i.e. those AF points at approximately the 2, 4, 8, and 10 o'clock positions. In particular, if you want to catch the moment, focus and recompose wastes too much time in between; usually the moment is gone by the time you recompose. That was the only way in the early days of AF because cameras back then had only 1 AF point. There are good reasons that the other 10 are also there now.

Carolyn if you have a chance to test you could try out the 12-24mm Nikkor zoom for very wide or/and the 17-55 F2.8 pro grade zoom. The latter is as sharp as a prime through most of its range.

Carolyn, there's always a possibility that your particilar Tamron isn't up to par, but really, as others have implied, and stated, it's the camera that's determining the focus point, not the lens.

 

If you use Capture NX, in post processing, it will tell you where the focus point actually was. I can't remember on the D80, but when shooting portraits, make the eyes the place where you set your focus. It's the first thing people look at in a portrait, and everything else is secondary. If the eyes aren't sharp, it usually doesn't matter if anything else is. Perhaps use a single sensor, but jockey it around until you have it where the person's eyes are. Also make sure your D80's focus points are set to light up in the viewfinder.

 

Lenses are generally so goo, I doubt if the Tamron is going to blow away what you've already got, but if you have a representative sample, then you should have a fine lens.

I have a couple of thoughts about this... Did you change the focal length after you locked

focus? Some zoom lenses are "varifocal" which means they do not remain in focus when

the focal length has been changed. "Parfocal" lenses stay in focus even when the focal

length is changed. If the literature that accompanied the lens doesn't mention it, the

quickest way to find out what kind of lens you have is to contact the manufacturer.

 

When using my 12-24 zoom I have found that it focuses better at 24mm; it is as if the AF

sensor doesn't have enough info to focus quickly at wide-angle. So I tend to focus at

24mm and then change the focal length. In my case the Tokina zoom I use is parfocal.

 

I do not care for auto focus in most situations, and I really do not like having AF tied to the

shutter release. Having to lock focus and then recompose my shot is adding needless

steps. And if you happen to lift your finger off the shutter then focus can be lost without

you realizing it.

 

I have addressed this problem by programming the D80 AF-L/AE-L button to control auto

focus and I have AF set to AF-C. I don't have to be concerned about holding the shutter

half-way and the focus remains the same until I press the AF-L/AE-L button. This is

particularly useful when using wide angle lenses when the increased depth of field doesn't

require exact focus. I am having to get accustomed to focusing using the button, but the

results are worth the effort.

Well, 1st of all, the 18-70mm Nikon lens is a pretty darn good optic, so the Tamron 17-50mm would not show all that much better, other than being around 1 stop faster. Other folks have given you good advice about proper use of the autofocus sensors, and I have nothing to add to that. But really, the Tamron is NOT an ultra wide lens it's a wide to normal lens, so it would not be expected to be very different at all from a good wide to short tele like your 18-70mm Nikon lens, outside of being a bit faster. A REALLY wide angle (on an APS sensor ) would be something that got you down to the 11-14mm range. Now those lenses would show you a noticeably wider field of view at the wide end, and they would probably be better corrected for linear distortion than your 18-70 (or probably even your 17-50 Tamron), but the distortion improvement is a rather subtle difference for most types of subject matter (see the slight curvature in the horizontal fenceposts in the first photo - that would probably be lessened). But, I would really NOT expect much visible difference between a good 17-50mm lens and a good 18-70mm lens when both are shot at 17 or 18mm settings. And frankly, if I already had the 18-70mm Nikon lens, I would never have bothered with that 17-50 Tamron as it was bound to not offer much more for you - rather, I'd have been looking at an ultra wide like the Sigma 10-20mm, Tamron 11-18mm or Nikon or Tokina 12-24mm lenses, for noticeably MORE wide angle effect when needed, and maybe a 50mm f1.8 for LOTS more speed when needed.

Maybe the problem lies in the focus-recompose-shoot-technique. If you recompose after focusing, the subject will eventually be moved out of

the focal plane. This problem is more pronounced with wider lenses since the change of the shooting direction when recomposing is mostly bigger than with long lenses.

You should maybe try to make use of the different focussing sensors your camera offers. Much less or no recomposing will be necessary then. After some practice, you will change the focussing sensor quickly and intuitively.

Just my 2c.

Just another point that helps me in similar situations when shooting moving objects at special moments: I put the D80 in "continuous shooting" mode and take 3 or 4 shots. Often one of the shots will be sharper than the others because my hands or the subject are moving less at that particular moment. AF-C is very responsive on the D80, but your chances of catching just the right shot under chaotic conditions are increased with multiple shots.

Just to echo much of what has already been said here. The advantage of the Tamron is a wider aperture when you need it. Turn off AF-Shutter, learn to use your thumb to activate AF using the AF-On button and move the AF sensors to where you want them. One thing that will help you is previsualizing how you want to compose the shot so that you are already using the appropriate AF sensor. Finally, get out the flash; that last shot is overexposed and needed to be metered differently with some flash fill to even out the DR.

Thanks all - this is such a great site for really good informative and intelligent advise.

 

The Tamron is on it's way back, no loss there, I don't even have to pay return shipping.

 

I used my 50mm 1.8 this afternoon/evening (5'ish) and came up with what I've been looking for. I was just hoping to find it more with a zoom. Below is a great example. Just wish he had a smile, but there's always tomorrow!

 

<a href="http://www.flickr.com/photos/carabell/653099825/" title="Photo Sharing"><img src="http://farm2.static.flickr.com/1173/653099825_7424c706d2.jpg" width="500" height="334" alt="sam on swing.jpg" /></a>

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and at 100% crop

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<a href="http://farm2.static.flickr.com/1004/653939408_298b0d94e8_b.jpg"> http://farm2.static.flickr.com/1004/653939408_298b0d94e8_b.jpg"</a>

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1/50ss, f3.5, ISO100 - shot in RAW, increased the blacks and the clarity and that's it.

 

I also worked with my flash - much sharper images but I'm not crazy about the fill flash look. I'll have to work on that one as well.