Sony 100mm STF
FE GM OSS Full-Frame E-Mount
Sample Images Intro Format Compatibility
Specifications Performance Recommendations
Sony FE 100mm STF G OSS (covers full-frame and APS-C, 72mm filters, 24.7 oz./700g, 1.9'/0.57m close focus, about $1,498). bigger.
I'd get mine at Adorama, at Amazon, at B&H or at Crutchfield.
This all-content, junk-free website's biggest source of support is when you use those or any of these links to my personally-approved sources when you get anything, regardless of the country in which you live. Sony does not seal its boxes in any way, so never buy at retail or any other source not on my personally approved list since you'll have no way of knowing if you're missing accessories, getting a defective, damaged, returned, non-USA, store demo or used lens. Get yours only from the approved sources I use myself for the best prices, service, return policies and selection. Thanks for helping me help you! Ken.
December 2017 Sony Sony Lenses Minolta Lenses Zeiss Canon Nikon All Reviews
Why Fixed Lenses Take Better Pictures
Sample Images
(more throughout the review)
Top Samples Intro Format Compatibility
Specs Performance Recommendations
This lens is all about smooth out-of-focus backgrounds. Here's a shot with a conventional 100mm lens:
Shot with conventional 24-105mm lens at 100mm. bigger.
And here's what we get with this STF lens:
Shot with this 100mm STF lens. bigger.
AHA! Just look how soft is the background. See how the out-of-focus discs become soft blobs?
Introduction
Top Samples Intro Format Compatibility
Specs Performance Recommendations
I buy only from these approved sources. I can't vouch for ads below. |
This Sony FE 100mm STF "Smooth Trans Focus" is a special lens designed for the smoothest possible out-of-focus backgrounds. This lens is ultra-sharp when in focus, and renders out-of-focus backgrounds more softly than regular lenses.
It has a special permanently-installed "apodization" filter near the diaphragm. In spite of the fancy name it's simply a clear filter that gets progressively darker towards its edges.
What this filter does at maximum aperture is turn out-of-focus points of light into soft-edged blobs instead of hard-edged circular discs as most lenses do. In other words, all lenses tend to render out-of-focus points of light as the same shape as the diaphragm, but if you add a special filter inside the lens to darken those edges, then the out-of-focus discs have darker edges than the centers, which turns the circular discs of regular lenses into softer blobs.
This is easier to show than describe. Here are two defocused shots of points of light. The lights are at 2m (6 feet) and each lens was focussed at 0.6m (2 feet):
Shot with conventional 24-105mm lens at 100mm. bigger.
Shot with this 100mm STF lens. bigger.
AHA!!! Huge difference! What are rendered as sharp discs with a normal lens look like soft blobs with this lens. Mathematicians would say that the discs have a rectangular distribution function, while this lens attempts a Gaussian distribution.
Because the internal filter loses light, what starts off as an f/2.8 lens only lets as much light through as an f/5.6 lens. Thus its transmission-equivalent T/stop is marked T5.6.
When stopped down, the lens is shooting through the clear central part of the filter, and behaves like every other 100mm lens.
Sony FE 100mm STF. bigger.
Good
● Super sharp.
● Super-soft backgrounds; great bokeh.
● Optical Image Stabilizer.
● Silent autofocus.
● Silent diaphragm operation.
● Autofocuses over the entire frame on an A9.
● Great bokeh.
● Focus Lock button.
Bad
● Autofocus is relatively slow — but silent.
Format
Top Samples Intro Format Compatibility
Specs Performance Recommendations
This is a full frame lens and I'm reviewing it as such.
It also works great on APS-C cameras, on which you may make the usual inferences.
Compatibility
Top Samples Intro Format Compatibility
Specs Performance Recommendations
This works on all Sony E-mount cameras, full-frame and APS-C crop-sensor. This includes all the variations of NEX, A9-, A7-, A6xxx and A5xxx series cameras.
It will not work on any Sony A-mount DSLR or any Minolta MAXXUM 35mm SLR of any kind. Those use the old A mount which was actually the Minolta MAXXUM mount from 1987.
Specifications
Top Samples Intro Format Compatibility
Specs Performance Recommendations
Name
Sony FE 100mm STF. bigger.
Sony calls this the Sony FE 100mm STF G OSS.
FE: Full-frame coverage, E-mount.
STF: Smooth Trans Focus.
GM: "G Master;" one of Sony's "Good" lenses for E-mount cameras.
OSS: Optical Steady Shot Image Stabilization.
It's Sony model number SEL100F28GM.
Optics
Sony 100 2.8 STF internal construction. Aspherical and ED elements. The blue flat is the dark-edged "apodization" filter. bigger.
13 elements in 10 groups.
One ED extra-low dispersion element to help reduce secondary axial chromatic aberration.
1 aspherical element.
Mutlicoated.
Nano coated.
Maximum Aperture
f/2.8.
Because of the dark-edged apodization filter this lens only transmits as much light as an f/5.6 lens, therefore it's also called T5.6.
Diaphragm
Sony FE 100mm STF. bigger.
11 rounded blades.
Stops down to f/20 (T22).
The diaphragm is silent as it operates on a silent camera.
Aperture Ring
Yes, electronic.
Focal Length
100mm.
When used on APS-C, it sees the same angle of view as a 150mm lens sees when used on a full-frame or 35mm camera.
See also Crop Factor.
Angle of View
24º diagonal on full-frame.
16º diagonal on APS-C.
Autofocus
Focus is internal. Nothing moves externally as focussed.
Sony says it uses a DDSSM (Direct Drive Super Sonic wave Motor) drive.
Focus is entirely electronic; both auto and manual focus work with a genuinely silent internal motor.
Focus-lock button.
Focus Scale
No.
Infinity Focus Stop
No.
Depth of Field Scale
No.
Infrared Focus Index
No.
Close Focus
1.9 feet (0.57 meters).
Maximum Reproduction Ratio
1:4.2 (0.24×).
Filters
Plastic 72 mm filter thread.
Hood
Included ALC-SH147 hood. bigger.
Plastic bayonet ALC-SH147 hood included.
Size
3.35" maximum diameter × 4.65" extension from flange.
85.2 mm maximum diameter × 118.1 mm extension from flange.
Weight
24.707 oz. (700.45g), actual measured.
Rated 24.7 oz. (700g).
Quality
Made in Thailand.
Announced
Announced at WPPI, February 2017.
Included
Lens (SEL100F28GM).
ALC-F72S front and ALC-R1EM rear cap.
ALC-SH147 hood.
Case.
Warranty.
Sony's Model Number
SEL100F28GM.
Price, USA
$1,498, December 2017.
Performance
Top Samples Intro Format Compatibility
Specs Performance Recommendations
Overall Autofocus Manual Focus
Breathing Bokeh Distortion Ergonomics
Falloff Filters Flare & Ghosts
Lateral Color Fringes Macro Mechanics
Overall
The Sony FE 100mm STF GM OSS is optically superb, as almost all 100mm fixed lenses are, and it has a clever internal filter to help make backgrounds super-smooth.
Autofocus
Autofocus is relatively slow.
It is silent.
Manual Focus
Manual focus is with an electronic ring on the front of the lens.
It's only lightly damped. A light fingertip will move it.
Focus Breathing
Focus breathing is the image changing size as focused in and out. It's important to cinematographers because it looks funny if the image changes size as focus gets pulled back and forth between actors. If the lens does this, the image "breathes" by growing and contracting slightly as the dialog goes back and forth.
The image from this 100/2.8 doesn't change noticeably as focussed.
Bokeh
Bokeh, the feel or quality of out-of-focus areas as opposed to how far out of focus they are, is extraordinary, the whole point of this lens. Nothing distracts:
Davis 6250 weather station, 8:55 AM, 19 December 2017. bigger or camera-original © file to explore on your computer (mobile devices rarely display full resolution images properly).
What makes this so special is how there are no hard edges to anything in the background; it's all melted away. With most lenses even out of focus areas tend to have slight edges to them, but with the dark-edged filter near the diaphragm these slight edges are gone.
As always, if you want to throw the background as far out of focus as possible, shoot wide open and get as close as possible.
Distortion
The Sony 100/2.8 STF has moderate pincushion distortion. Use a factor of -2.50 in Photoshop's lens distortion filter to correct it fully at 3m/10 feet.
Most Sony cameras have automatic distortion correction which you can activate in the camera's Lens Comp. menu.
Ergonomics
Sony FE 100mm STF. bigger.
It has an electronic focus ring, an aperture ring with defeatable clicks, and a focus range selector.
The focus ring turns with a single fingertip.
The aperture ring wants a strong single finger, or two fingers, to move it.
The focus range selector isn't electronic — it actually moves the entire lens forward or back inside the barrel!
The left side has a big, unmarked focus lock button. The focus lock button can be handy to hold focus and recompose — although to be honest on a camera like the A9 that focuses all over the entire frame, this isn't as necessary as it was with DSLRs that only focussed in the center.
There's also an AF/MF slide switch and another for the stabilizer. These switches fall right under my thumb where they should:
Sony FE 100mm STF. bigger.
The left side has a slide switch that can engage or disengage the aperture ring clicks.
Sony FE 100mm STF. bigger.
Falloff
There is no significant falloff at any aperture, at least on most Sony cameras which correct it by default.
Filters, use with
No problem; 72mm is a more than an ample filter size for the optics of this lens. Even on full-frame you can stack several filters before you see any vignetting.
Go ahead and use any normal filters and thick rotating polarizer and grad filters; there's no problem.
Flare & Ghosts
This lens has no significant ghosts. Only if you really go out of your way pointing it at the sun and have the rest of the frame filled with something in shadow can you see even the slightest green ghost:
Shot directly into the sun at f/8. bigger.
You won't see any flare or ghosts in actual use. In this case the sun was so strong that this picture has more detail in the tree than I could see with my naked eye staring into the sun like this!
Lateral Color Fringes
There are no color fringes as shot on my Sony A7R III, which corrects them by default if there are any.
Macro
It gets reasonably close; much closer than typical 85mm to 105mm portrait lenses do.
Anything not in perfect focus may have color fringes due to spherochromatism; this is normal and goes away when in perfect focus.
Kienzle Flieger Automat 800/2843 in last light, 4:18 PM, 21 December 2017. Full-frame Sony A7R III,at f/6.3 at 1/125 at close focus distance at Auto ISO 100. bigger or camera-original © file to explore on your computer (mobile devices rarely display full resolution images properly).
1,200 × 900 pixel crop from above. bigger or camera-original © file to explore on your computer (mobile devices rarely display full resolution images properly).
If this crop is about 6" (15cm) wide on your screen, then the complete image printed at this same extreme magnification would be about 27 × 40" (67 × 100 cm).
If this crop is about 12" (30cm) wide on your screen, then the complete image printed at this same extreme magnification would be about 53 × 80" (1.35 × 2 meters).
If you don't get perfect focus, spherochromatism will be visible.
Mechanical Quality
Sony FE 100mm STF. bigger.
It's a mostly tough lens with a good mix of metal and plastic.
Included Hood
Plastic bayonet.
Front Bumper
None.
Filter Threads
Plastic.
Hood Bayonet Mount
Plastic.
Front Barrel
Part ahead of focus ring: metal.
Focus Ring
Rubber covered metal.
Front Mid Barrel
Part with focus-lock button: Plastic.
Aperture Ring
Metal.
Rear Mid Barrel
Part with slide switches: Plastic.
Locking Focus Range Ring
Metal.
Rear Barrel
Plastic.
Serial Number
Printed on sticker glued on bottom of barrel - not exactly a classy way to do this.
Moisture Seal at Mount
Yes.
Mount
Chromed metal.
Identity & Markings
Raised metallic lettering on top of barrel and painted elsewhere.
Internals
Mostly plastic.
Date Code
None found on lens, but it is marked on the box. Be sure the serial number on the box (in the middle of the number below the second bar code) matches the serial number printed on the sticker on the bottom of the lens.
Noises When Shaken
Minor to moderate clunking.
Made in
Thailand.
Sony hides this in black-on-black molded on the top of the plastic light shield on the back of the lens opposite the gold contacts that's only visible with the lens off a camera and without its rear cap.
Sharpness
It's flawlessly sharp and contrasty from corner-to-corner at every aperture.
The only limitation to picture sharpness will be your skill as a photographer..
Here are Sony's MTF charts at 10 cyc/mm and 30 cyc/mm, radial (solid) and tangential (dotted), which tell the same story:
 |
 |
MTF at f/2.8. bigger. |
MTF at f/8. bigger. |
This is an insanely good claimed MTF.
Spherochromatism
Spherochromatism, also called "color bokeh" by laymen, can cause colored fringes on out-of-focus highlights, usually seen as green fringes on backgrounds and magenta fringes on foregrounds. It's an advanced form of chromatic aberration in a different dimension than lateral color. Spherochromatism is most commonly seen in fast lenses of moderate focal length when shooting contrasty items at full aperture. It goes away stopped down.
The Sony 100 2.8 STF has a moderate amount of spherochromatism, seen as magenta-red (near) and yellow-green (far) color fringes in areas that aren't in perfect focus:
Kienzle Flieger Automat 800/2843 in last light, 4:20 PM, 21 December 2017. Full-frame Sony A7R III,at f/2.8 (T5.6) at 1/80 at Auto ISO 100. bigger or camera-original © file to explore on your computer (mobile devices rarely display full resolution images properly).
1,200 × 900 pixel crop from above. bigger or camera-original © file to explore on your computer (mobile devices rarely display full resolution images properly).
If this crop is about 6" (15cm) wide on your screen, then the complete image printed at this same extreme magnification would be about 27 × 40" (67 × 100 cm).
If this crop is about 12" (30cm) wide on your screen, then the complete image printed at this same extreme magnification would be about 53 × 80" (1.35 × 2 meters).
Image Stabilization
The built-in optical stabilizer works great, locking-down images for sharp shots at much slower shutter speeds than you'd expect.
Sunstars
The rounded blades prevent sunstars at most apertures. Even at f/22 there isn't much. Here's about the best you'll get. Click any to enlarge:
Recommendations
Top Samples Intro Format Compatibility
Specs Performance Recommendations
This is a very special lens optimized for shooting portraits and headshots. It's a great medium telephoto, but expensive unless you really need the ultrasoft backgrounds for which you're paying extra.
This is not a high speed lens; it's a bad choice for low light. For low light, get the Sony 85mm f/1.4 GM instead which is four stops faster and focuses faster, too. The 85/1.4 lacks a stabilizer and doesn't focus as close.
I use a clear (UV) protective filter instead of a cap. I only use a cap when I throw this in my bag, otherwise I leave a clear filter on my lens at all times.
The very best protective filter is the 72mm Hoya multicoated HD3 UV which uses hardened glass and repels dirt and fingerprints.
For less money, the B+W 72mm 010 is an excellent filter, as are the multicoated version and the basic multicoated Hoya filters, but the Hoya HD3 is the toughest and the best.
Filters last a lifetime, so you may as well get the best. The Hoya HD3 stays cleaner than the others since it repels oil and dirt.
I'd get my 100mm f/2.8 STF at Adorama, at Amazon, at B&H or at Crutchfield.
This all-content, junk-free website's biggest source of support is when you use those or any of these links to approved sources when you get anything, regardless of the country in which you live. Sony does not seal its boxes in any way, so never buy at retail or any other source not on my personally approved list since you'll have no way of knowing if you're missing accessories, getting a defective, damaged, returned, non-USA, store demo or used lens. I use the stores I do because they ship from secure remote warehouses where no one gets to touch your new camera before you do. Buy only from the approved sources I use myself for the best prices, service, return policies and selection.
Thanks for helping me help you!
Ken, Mrs. Rockwell, Ryan and Katie.
© Ken Rockwell. All rights reserved. Tous droits réservés. Alle Rechte vorbehalten.
Help Me Help You
I support my growing family through this website, as crazy as it might seem.
The biggest help is when you use any of these links when you get anything. It costs you nothing, and is this site's, and thus my family's, biggest source of support. These places always have the best prices and service, which is why I've used them since before this website existed. I recommend them all personally.
If you find this page as helpful as a book you might have had to buy or a workshop you may have had to take, feel free to help me continue helping everyone.
If you've gotten your gear through one of my links or helped otherwise, you're family. It's great people like you who allow me to keep adding to this site full-time. Thanks!
If you haven't helped yet, please do, and consider helping me with a gift of $5.00.
As this page is copyrighted and formally registered, it is unlawful to make copies, especially in the form of printouts for personal use. If you wish to make a printout for personal use, you are granted one-time permission only if you PayPal me $5.00 per printout or part thereof. Thank you!
Thanks for reading!
Mr. & Mrs. Ken Rockwell, Ryan and Katie.