Sony DT 18-135mm F/3.5-5.6 SAM Review - Photo Jottings

Sony DT 18-135mm F/3.5-5.6 SAM Review

2012summer/s18135box.jpg
Box and contents
The Sony A77 was used for this review.  For a better understanding of terms and methods used in this review, go here.
The usual center, mid-section and corner crops are located below the conclusion.
Don’t forget to check out the bonus section at the bottom of the page where I compare this lens to the Sony CZ 16-80mm F/3.5-4.5.
 
Introduction.
Sony introduces another ‘DT’ travel zoom for the alpha mount, this time with a focal length of 18-135mm, or 27-202mm in 135 format.  Other ‘DT’ travel zooms by Sony are the 18-200mm, and 18-250mm, both reviewed here.
The Sony DT 18-135mm F/3.5-5.6 SAM has a good build quality, with a metal mount (appears to be aluminum or pot metal) and high quality plastic for the body.  It feels solid and smooth in the hand.  Appearance wise, it has a slightly speckled satin black finish, very similar to Sony camera bodies.  Outside features include a handy zoom lock, AF/MF switch on the left side to turn off the SAM, ribbed rubber manual focusing ring at the back, and a large zoom ring at the front with focal length marks at 18mm, 24mm, 35mm, 50mm, 70mm, 100mm and 135mm.  Inside, you will find one ‘ED’, and two aspherical elements according to Sony’s user’s manual.  The lens says “made in Japan.”
Zooming is smooth, and damped appropriately in my opinion.  It does have a zoom lock, (locks only at 18mm) but you probably won’t need it.  Zooming all the way out increases the length by 2.2″ (57mm), using a two piece plastic extension tube
EXIF focal length data records correctly at all marks.
Inside the box is the lens, front and rear caps, plastic petal type hood, and owner’s manual.
Focusing.  This lens uses Sony’s second generation SAM system to provide focusing, which is substantially quieter and quicker than the standard ‘SAM’ type, or the old slot-screw type system that was used for most Minolta, and later re-branded Sony lenses, however, it still isn’t as quiet as the ‘SSM’ type system.  All focusing is done internally, which means the filter ring doesn’t move, so your polarizing and graduated neutral density filters will stay in the position you originally set them in.  The focusing ring turns about 90°, which allows precise manual focusing, although the ring itself doesn’t move during AF operation.  Focusing speed is very quick, with a high degree of accuracy on my A77, however, your results may vary depending on the calibration of your particular lens and camera.
This lens allows you to instantly override AF and focus manually without having to push any buttons.  You simply engage the AF with a shutter button half press, release, and adjust the focus manually as desired, the AF system is canceled until you half press the shutter button again.
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Requisite product shots.

2012summer/s18135sdret.jpg
Side shot showing zoom lock
2012summer/s18135sdex.jpg
Full zoom extension
2012summer/s18135bk.jpg
Metal mount and AF/MF switch.
2012summer/s18135ft.jpg
Front element
2012summer/s18135mtf.jpg
Sony X-ray view and MTF chart
General information and specifications.

Lens
Box contents
Front cap, rear cap, hood, and users manual.
Cost
Approximately $499
Build quality
Good to very good.
Additional information
Other good travel zooms from Sony include; 18-200mm, 18-250mm, and the16-105mm.
Specifications below
Optical configuration
14 elements in 11 groups
Angle of view
76˚-12° APS-C
Aperture
7 blades, curved
Full frame and APS-C
Made for APS-C cameras only, but will work on full frame using APS-C size capture.  Equivalent to 27-202mm in 135 format.
Depth of field and focus scales?
Nothing
Minimum focus, image plane to subject
About 16″  (406mm)
Minimum focus, end of lens barrel to subject
About 8.4″  (213mm)
Hard stop at infinity focus?
No.
Length changes when focusing?
No.
Focus ring turns in AF?
No
Filter size
62mm
Filter ring rotates?
No
Distance encoder?
Yes
Max magnification
1:4 or 0.25x
Min. F/stop
F/22-36
Sony teleconverter compatible?
No
Length changes when zooming?
Yes
Dimensions WxL  (my measurements)
3.00″ x 3.39″   76mm x 86mm
Maximum  extended length (my measurements)
5.6″  (143mm).
Weight bare (my scale)
13.9oz  (395g) bare
Optical qualities summary.
Lens flare/ghosting.  Average control.  Small green/orange blobs show up at all focal lengths when super bright lights are in the image, see examples below.
Light fall-off.  Minor amounts at the wide end.
Color fringing (CA).  Lateral color fringing control is about average for a modern wide to medium telephoto zoom.  I see magenta and cyan along the edges of the image, however, all modern Sony cameras will correct this by default.  See uncorrected sample crops below the conclusion.
Bokeh.  Poor at the wide end; not bad at the long end.  See examples below.
Color.   Same as other Sony lenses.
Close up filter.  N/A
Coma.  Basically none.
Regular filters cause very slight additional light fall-off at 18mm, but this isn’t something you’ll ever notice in real life.
Filter size.  62mm.  Sharing this size in the Sony DT line-up are the Carl Zeiss 16-80mm, 16-105mm, 18-200mm, 18-250mm, and the 70-300mm G.
Distortion.  Strong barrel distortion, to minor pincushion depending on focal length, see samples below.
2012summer/s18135dis18un.jpg
Strong, wavy barrel distortion at 18mm, uncorrected.
2012summer/s18135dis18corr.jpg
18mm, with lens comp distortion on.
2012summer/s18135dis24un.jpg
Wavy but relatively flat distortion at 24mm, uncorrected.
2012summer/s18135dis24corr.jpg
24mm, with lens comp distortion on.
2012summer/s18135dis50un.jpg
Moderate pincushion distortion at 50mm, uncorrected.
2012summer/s18135dis50corr.jpg
50mm, with lens comp distortion on.
2012summer/s18135dis135un.jpg
Minor pincushion distortion at 135mm.
2012summer/s18135dis135corr.jpg
135mm, with lens comp distortion on.

 

The barrel distortion produced by this lens at the wide end is strong, and impossible to fix with common image editing software, but with ‘lens comp distortion’ turned on (if available on your camera), it’s pretty straight.  As you zoom out to 50mm and beyond, the distortion pattern turns to pincushion, but is easily fixed either by the camera, or by using lens distortion sliders in better photo imaging software.

 

 

Bokeh samples.

 

          18mm   F/3.5
            18mm   F/5.6
2012summer/18135bok35w.jpg
2012summer/18135bok56w.jpg
           135mm  F/5.6
             135mm  F/8
2012summer/18135bok56tt.jpg
2012summer/18135bok80tt.jpg

 

Bokeh looks pretty harsh at shorter focal lengths, but that’s typical for this type of lens.  At the long end highlight blur looks somewhat smooth.  Bokeh is the character of out of focus highlights, and not simply how far out of focus the background is.

Light fall-off samples.
          18mm   F/3.5
            18mm   F/5.6
2012summer/s18135vig1835.jpg
2012summer/s18135vig1856.jpg
           135mm  F/5.6
             135mm  F/8
2012summer/s18135vig13556.jpg
2012summer/s18135vig13580.jpg

 

Light fall-off is not a problem on this lens at any focal length.  Using a regular filter will cause slightly more light fall-off at the short end at F/3.5, although you won’t know it unless you compare ‘with’, and ‘without’ images.  I do that for testing, but you don’t need to do that at home.

 

 

Flare and  ghosting.

 

Green and orange blobs; 18mm, F/5.
Flare and ghosts; 40mm, sun in shot, F/5.6.
2012summer/18f5gst1.jpg
2012summer/40f56gst2.jpg
Ghosting control is about average for a modern zoom lens.  When the sun is in, or at the edge of the image, green/orange colored blobs and arcs might be visible, such as what you see above.  Use your hand to block bright light sources when they’re out of the image, even if the hood is on, especially at the wide end.

 

Aperture/focal length guide.

 

Maximum aperture
       F/3.5
       F/4
       F/4.5
       F/5
       F/5.6
Range
18-20mm
20-30mm
30-45mm
50-60mm
60-135mm
Focal length numbers carry through between apertures, which is normal.  You may get slightly different numbers if you want to spend all day firing off shots and moving the zoom ring in tiny increments.
 
 
Let’s check out the close focus capabilities of this lens.

The sample shot was taken with the Sony A77 24MP camera, so don’t compare it with some others that were taken with the 12.2mp A700, or 16mp A580.  The subject is a standard US stamp, 0.87″x 1.0″ or 22mm x 25mm.  Also, note the macro shot was taken as close to the subject as focusing allowed; in this case 8.4″ (213mm), measured from the front of the lens barrel to the subject.  
 
Reproduction size is average for a newer zoom lens (0.25x or 1:4), click for cropped image.  The stamp looks reasonably sharp, but lacks contrast at all apertures—ho hum.  As a side note; the “1996” on the bottom left of the stamp measures a mere 1mm wide.  
As close as you can get, F/8.
Conclusion. 

The Sony DT 18-135mm F/3.5-5.6 SAM is a welcome addition to the Sony lens line-up, but not really for the optical performance or zoom range.  What’s actually welcome is the updated ‘SAM’ focusing (quieter and faster than the old ‘SAM’) with well implemented direct manual focusing, and the new metal mount; ok it’s cheap, but better than plastic.

 

Optically, this lens is not a masterpiece, but it did turn in a decent review.  The problem with choosing this lens is that it falls awfully close to other Sony travel zooms, like the Sony 18-200mm, or 18-250mm, both offer much more at the long end but are about the same size and weight, with the price being about the same or a little more.  I don’t have either of those super zooms handy for comparison, but based on memory, I’d say the optical performance is similar at the same focal lengths, but you do get better focusing all the way around with the 18-135mm.  Also, as of this review, the 18-200mm is not covered in the camera lens compensations for distortion, color fringing and light fall-off.

 

Bottom line; I would recommend the Sony 18-135mm for photographers looking at this focal range, and want a lens that’s fully compatible with the latest Sony cameras; and I’m talking about AF speed for fast action, lens corrections, and a quiet focus motor for discrete stills or video.  If you have more money to spend, and optical performance is more important than zoom range, look carefully at the CZ 16-80mm, or Sony 16-105mm.

 

If you’ve enjoyed this review, and are thinking of purchasing this lens or any other stuff, please use my B&H photo affiliate links, I get a small portion of each sale, but it doesn’t cost you a penny more.  It helps pay the rather high cost of running the website, thanks!

 

 

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Sample crops from the centers, mid-sections and corners.

 

18mm.

2012summer/18135fi18mm2.jpg
Full resized image
          Center
          Mid-section
             Corner
F/3.5
2012summer/s18135ctr35.jpg
2012summer/s18135mid35.jpg
2012summer/s18135corn35.jpg
F/5.6
2012summer/s18135ctr56.jpg
2012summer/s18135mid56.jpg
2012summer/s18135corn56.jpg
F/8
2012summer/s18135ctr80.jpg
2012summer/s18135mid80.jpg
2012summer/s18135corn80.jpg
F/11
2012summer/s18135ctr11.jpg
2012summer/s18135mid11.jpg
2012summer/s18135corn11.jpg

 

I see very sharp centers, with a little better contrast about one stop down from the maximum aperture.  The mid-sections are pretty sharp at F/5.6-8, but the corners are a little mushy at all apertures.  Diffraction set in at F/11, but landscapers might use it to make sure the image sides are reasonably sharp.

 

50mm.

2012summer/18135fi50mmm2.jpg
Full resized image
          Center
          Mid-section
             Corner
F/5.6
2012summer/s18135ctr5650mm.jpg
2012summer/s18135mid5650mm.jpg
2012summer/s18135corn5650mm.jpg
F/8
2012summer/s18135ctr8050mm.jpg
2012summer/s18135mid8050mm.jpg
2012summer/s18135corn8050mm.jpg
F/11
2012summer/s18135ctr1150mm.jpg
2012summer/s18135mid1150mm.jpg
2012summer/s18135corn1150mm.jpg

 

The zoom length around 50mm shows some sharp crops at F/5.6-8.  I see a very sharp image, even along the sides and in the extreme corners.

 

135mm.

2012summer/18135fi135mm2.jpg
Full resized image
          Center
          Mid-section
             Corner
F/5.6
2012summer/s18135ctr56135.jpg
2012summer/s18135mid56135.jpg
2012summer/s18135corn56135.jpg
F/8
2012summer/s18135ctr80135.jpg
2012summer/s18135mid80135.jpg
2012summer/s18135corn80135.jpg
F/11
2012summer/s18135ctr11135.jpg
2012summer/s18135mid11135.jpg
2012summer/s18135corn11135.jpg

 

Performance at the longer zoom lengths is good in the centers slightly stopped down, but stays soft along the image sides, with the corners being mush at all apertures.  Unfortunately, that’s par for the course with less-expensive travel zooms.

 

All images were taken in RAW, without any camera corrections, and cropped and converted to jpegs for viewing here.

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Bonus section!

 

Comparisons between the Sony 18-135mm and Carl Zeiss 16-80mm.  All image crops were taken at F/5.6 using the now standard boring, but relevant stamp scene.  Don’t compare image crops between focal length sets because the camera was moved for each focal length.

 

18mm

          Center
          Mid-section
             Corner
Sony 18-135mm
2012summer/18135ctr18.jpg
2012summer/18135mid18.jpg
2012summer/18135cor18.jpg
CZ 16-80mm
2012summer/czctr16.jpg
2012summer/czmid16.jpg
2012summer/czcor162.jpg

 

The CZ 16-80mm is still out resolving the 18-135mm even though I used it at 16mm.

 

 

50mm.

          Center
          Mid-section
             Corner
Sony 18-135mm
2012summer/18135ctr56x.jpg
2012summer/18135mid56x.jpg
2012summer/18135cor56x.jpg
CZ 16-80mm
2012summer/1680zctr56.jpg
2012summer/1680zmid56.jpg
2012summer/1680zcor56.jpg

 

Things change here as the 18-135mm looks very good across the entire image, even out performing the CZ 16-80mm at this length.

 

80mm.

          Center
          Mid-section
             Corner
Sony 18-135mm
2012summer/18135ctr80.jpg
2012summer/18135mid80.jpg
2012summer/18135cor80.jpg
CZ 16-80mm
2012summer/czctr80.jpg
2012summer/czmid80.jpg
2012summer/czcor80.jpg

 

Performance at 80mm is good for both lenses, but the 18-135mm is mushy in the corners.

 

Well, that’s it, hope you enjoyed the review, if so, please use my B&H Photo links when looking for your camera goodies, it helps pay the bills, and keeps me adding useful information to the site, thanks!

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