Jun 29 2019

Smooth Transition Focus – Simulation with the Minolta Maxxum 7

I guess a little explanation is in order.  Smooth Transition Focus (STF) is where within the lens design there is an apodization element placed near the aperture of the lens.  It acts like a circular graduated neutral density filter with the purpose of reducing the light from the outer edges. The gradual diffusion of the perimeter light results in the out of focus regions also being softer and more defuse while leaving the area of focus that passes through the center unimpacted and sharp.

As described by Sony (Minolta)

That’s how it is done optically but there is a camera that can simulate the effect.  The Minolta Maxxum 7 has a custom mode called STF where it takes multiple images at different apertures all on the same piece of film.  The out of focus areas all have different characteristics blended together while the in focus area is very much the same across all the apertures.

You can see the result if you look at the background of these images.  The busier of the two is from a single exposure at f4.5 and the second is using STF blending 7 exposures at T6.7.  It works as advertised stacking the multiple images for a smoother transition and a better blurring of the background.

I did a little test using the same idea to create STF images in camera with my Pentax K-3 to see how well it works.

One immediate drawback of this method is of course nothing can move between exposures. The GIF below contains on exposure at f8.0 and another one with 7 exposure from f3.5 to f8.0 as an initial test before any effort to do it in the wild

And here is what it looks like if you take things to extremes.  With 15 exposures from f1.2 to 5.6 if you look closely at the highlights you can see the different exposures not quite blended well enough.

I will get back to doing it in more detail with the K-3 at a later date. So how to do this with the Maxxum 7?  First is requires delving into the Custom menu.  Under the metal flap below the LCD you will find a row of buttons.

Pressing the CUSTOM button brings up that menu then using the left and right of the focus area selection pad you can navigate to custom function 25.  There are two settings at this point and pressing up and down on the focus pad will toggle between them.  What you want to do is select number two “STF mode”.

Once this is done selecting number 3 on the mode dial will put the camera into STF mode.

Pressing the shutter now will result in 7 images being rapidly taken as the camera changes the aperture between them.  So you had better have the camera mounted on a solid tripod.

Smooth Transition T6.7

Jun 22 2019

Portra 160

Back in 2011 Kodak updated Portra 160 using the technologies from their motion picture Vision films.  While Portra 160 does have a finer grain structure than Portra 400 they have it rated for sharpness even a tiny amount bellow Portra800. Its grain though falls between Portra 400 and Ektar 100 which is claimed to be the finest grained colour negative film ever.


Given all this it should perform similar to Portra 400 but with a slightly lower sensitivity and perhaps every so slightly softer which may be why Kodak present it as a film ideal for portraiture.

You can see that 160 and 400 have similarly shaped spectral curves that differ from Ektar 100. The images from Portra 160 & 400 emulsions properly exposed should therefore give similar results which is what I have found.


This is one of the reasons I gravitate towards Portra 400 rather than 160 I rarely find myself in a situation where there is just too much light to shoot 400.  And given the abilities of these films to handle over exposure of several stops it just isn’t a problem shooting 400 speed film.  Also with a hybrid film to digital workflow there is always the ability to make some adjustments.  So while I do use Portra 160 from time to time as seen in the images below I prefer Portra 400 for its versatility.

You can find more info around Kodak Alaris films here

Kodak Alaris

Jun 8 2019

Canon QL17 III


In 1971 Canon was advertising the Canon QL17 as a carry-it-anyplace camera that gave quick and precise rangefinder focusing and that it was the most automatic precision camera you can buy but that it could be used 100% manually if you prefer.


My camera is actually the QL17 G-III but there is little difference between them.

It may have been superseded as the most automatic precision camera you can buy in the last 48 years but it is still an easy to carry precision rangefinder.  The lens of the QL17 is a 45mm f1.7 constructed with 6 elements in 5 groups. and is a fantastic performer.  The image bellow shows details from the corners and center without any editing.  You can see there is just a tiny amount of chromatic aberration but the entire field is sharp.  This image was taken with the lens stopped down but it is good even wide open.

CanonQL17_Portra400_2018_034-Edit copy

The shutter a Copal SV has a top speed of 1/500 second and can be used without a battery which is fortunate because the camera was originally designed to use a 1.3V mercury cell.

So there is good reason that this camera is still well regarded its just a great little fixed lens rangefinder.

Jun 1 2019

Olympus Stylus 150


Released in 2003 six years after the much better and more desirable Olympus Stylus Epic the Stylus 150 marked the end of new film cameras from almost all camera makers as they focused their efforts exclusively on digital cameras ( I believe the Stylus Epic Zoom 170 was released before the 150) .  And that’s okay because cameras like this had reached their limit and maybe even pushed a little too far.  What I mean is at an aperture of f13.3 and a focal length of 150mm it reaches beyond where it should.  Without a lot of light the camera is going to be forced to use slower shutter speeds than should be used.  There is a mode that is intended to counteract this it is the camera shake mode under the flash menu.  Olympus isn’t very clear about how this functions.  In the manual it says that if the green and orange LED’s around the viewfinder are alternately blinking then there is a potentially for too much camera shake and to hold the camera securely until the blinking stops.  This suggests that there is a sensor in the camera that is measuring the shake.  In a brochure for the camera they say it a little differently.

Camera Shake Indicator: This innovative feature prompts you to steady the camera when shake is detected. Even if movement continues, it automatically selects a faster shutter speed to reduce image blur.

How effective this is isn’t clear but that fact that they were making this effort is another indication of the problem that these long zoom compact cameras were suffering from.

The specifications for the lens on the Stylus 150 is  37.5 ~ 150 mm, F5.1 ~ 13.3, 8 elements in 7 groups.


A previous post about the Olympus Stylus 150 can be seen here Stylus 15o