I had the pleasure of borrowing a Minolta Dynax 7 and ran a few rolls of film through it. One of the unique features of this camera is its ability to simulate an STF lens under certain conditions. An STF lens uses a special optical formula that includes a special internal filter to create smooth out of focus areas. The simulation however achieves this by taking 7 exposures on a single frame of film each with a different aperture setting. The blended image has a soft blurry out of focus area while retaining the same degree of sharpness in the areas that were in focus. The aperture is determined by the maximum speed of the lens itself so with a lens with a maximum opening of f1.7 the seven 1/3 stop increments takes you to f2.8 if the lens however has a maximum opening of around f3.5 then it would start at f6.7 and work its way down in 1/3 stops to f3.5.
While I don’t believe there is any other camera that has ever automated this SFT function before I thought it would be fun to see what I could do using my Pentax K-3. Pentax has many unique features in their cameras and the K-3 has an extensive set of multiple exposure settings. I settled on using Multi-exposure with 7 shots set to Average mode for the compositing primarily because that is the number of images the Minolta uses. I then put the camera in aperture priority mode allowing the camera to meter the scene and select the shutter speed but using positive exposure compensation because of the massive amount of backlighting I used during testing of the idea. Then I selected a starting aperture and exposed the first frame. I then increased the aperture by 1/3 stop and took the second frame and so on until all 7 images were composited. And it worked. The total amount of light gathered for all 7 images was approximately the same as a single frame exposed at that aperture but now the out of focus areas were averaged out while the in focus areas remained the same. I should also mention I used a very heavy studio tripod that was weighted down, any movement during or between any of the exposures and the whole thing is for naught. Maybe I should recap because that’s a lot of information.
1. Secure the camera well there can be no movement
2. Set the camera’s drive mode to Multiple-exposure
3. Set the number of exposures your going to use (this is the number of 1/3 aperture steps you will make)
4. Set the compositing mode to average
5. Select your starting aperture (you can either go up or down but the idea will be to either start or end with the lens wide open)
6. Take your first exposure
7. Alter your aperture by 1/3 stop with the control wheel (Allow the camera to change the shutter speed to maintain the exposure)
8. Repeat step 7 until all the frames have been taken.
9. Your done enjoy
Here are two images for comparison the first is a single exposure at f5.6 and the second is 15 exposures from f5.6 to f1.2
While the in focus areas are roughly the same the background has been averaged out more by using the multiple exposures. You can actually see the steps of each exposure in the overexposed backlight area. This was as extreme of an example as I could create and not something you would likely be taking pictures of. The mirror ball represents a more realistic real world result. You could just take a number of images with varying apertures and combine them after the fact on a computer but I wanted to see how close I could come to recreating the Minolta method in camera. Everything is already there Pentax could just automate the process.
Here are two more examples with a light transmission of f8.0 The first one is a single exposure and the second one is 7 separate ones from f8.0 to f3.5
And just for good measure here is the Pentax 50 1.2 shot wide open because I can.
Here are a few real world examples comparing shooting with single apertures vs multiple exposures.
The Stereo Revere is an attractive camera which looks great on display. Unfortunately mine is having issues with advancing the film and the result is some massively multiple exposed images. There are times when this could be interesting but I had been hoping to be able to create stereoscopic images.
Looking at the front of the Stereo Revere 33 you can see it has three distinct viewfinder related rectangles. This is because it has a separate rangefinder for focusing and a viewfinder for composition. looking through one and then the other slows down the process but is better than zone focusing.
Perhaps I should just let the pictures speak for themselves and if your interested in more info you can explore some of my other posts about this camera.
Using the Konica A4 became a little bit of a film rescue mission. Not too far into the roll the camera stopped advancing and shooting and refused to rewind. So it became necessary to open it up in my film changing bag and pull the film out and manually wind it back into the canister. The film itself is some seriously out of date Fuji 200.
The Konica A4 came out in 1989 but was quickly replaced with the much better known and specified Konica Big Mini a year later. The A4’s position in camera history is therefore more that it was the progenitor of the Big Mini
The A4 does have a nice 35mm f3.5 lens which I think I will harvest for future experimentation.
The Vivitar Ultrawide and slim is one of those rare plastic cameras that have achieved a status beyond what could have originally been conceived. This is of course due to its unique 22mm f11 lens. And to a lesser extent how thin the camera is. This is also because of the lens and its construction. Now I could have just left it as it was and it would have been fine but I wanted to see if I could “improve” things. And by improve I mean risk making the already poor image quality worse while making the lens faster. Technically what I did isn’t making the lens faster but if you consider the lens and fixed aperture as one I gave the entire system about 2 stops more light gathering ability. First a warning if you plan to do something similar there are springs inside that want to get out. The spring that tensions the shutter took a flying leap never to be seen again fortunately I have enough random bits that I was able to replace it.
So how do you go from f11 to f5.6 you might ask. First off apertures represent either the opening that light passing through a lens must go through or the light gathering ability of a lens. A large aperture represented by a smaller number such as f1.4 lets in more light than a small aperture represented by a larger numeric value such as f4 simple right? It is really I’m just trying to make it sound worse than it is. There is a standard scale of apertures each one representing twice the light gathering of the previous one. This list of full “f stops” go something like this f1.4,f2,f2.8,f4,f5.6,f8,f11,f16,f22. The area that we are interested in is f11 – f5.6 which we can see is a separation of 2 full stops along that scale. Again each stop represents twice the light gathering of the previous one. Because the physical aperture is circular it does not corollate to twice the diameter just twice the area for each stop and since the area is determined by the formula pi * radius squared I needed to double the radius to make the area 4 times as large. Anyhooo I measured the diameter of the hole with a micrometer at 1.4mm and drilled it out to 2.8mm which gives me four times the area and my f11 to f 5.6 alteration.
And the impact? Marginal it didn’t make the camera a low light monster. Granted I may have sped up the shutter speed with my spring replacement which would counter the aperture change but the image quality didn’t seem to suffer from allowing more of the lens to play a part in producing the images either. In the end with an aperture of f5.6 and a shutter speed somewhere around 1/125 second this Vivitar Ultrawide and Slim still craves light.
* the photographer may have definitely used expired film, side effects could include graininess rash and blocked shadows.
As much as I have wanted to like Portra 160 I just cant seem to come to terms with it. I am almost always happier with the results I get from Portra 400 and if I want to use a lower ISO film then Ektar 100 often fits the bill. This should have been a good pairing with the fast lens of the Konica Auto S3 and under good light it can be but that extra stop and a bit you give up from Portra 400 can really make the difference. Will I keep trying with Portra 160? Of course I will it has a niche somewhere I just need to find it for me.
At some point I acquired these cameras with the idea of running a roll of film through them and blogging about it but they have sat in the “Too be chosen bin” for awhile now with no sign of making it out. So I decided to apply a new test or more accurately a thought experiment. Would I want to expend a roll of Kodak Portra 400 in them, and they were found lacking. Looking at them all sitting there it has become clear to me that its the 38mm wide end. The no mans land of focal lengths. Not nearly wide enough and the telephoto end isn’t that spectacular either. The Minolta has the nicest finish and the Pentax is the most ubiquitous, you almost always need to push some aside to get at the other cameras at a thrift store. So for not having made the cut these ones will find their way back to a thrift store. I just need to make sure I don’t buy them back accidently.
Back in the early 1980’s the Olympus XA was quickly adopted by many photographers as a pocket camera for many reasons. It was small and pocketable but it also produced good results. This of course is due to the lens which is made using 6 elements in 5 groups. (That’s where the F Zuiko comes from, F is the 6th letter in the alphabet E would denote 5 elements and G would be 7). The lens focusing is done not with the front element as is particularly familiar with small film cameras but is done using internal elements. The electronically controlled shutter also sits between lens elements. The shutter operates all the way from 10 seconds to 1/500sec so properly secured the XA can be used for relatively long exposures.
The rangefinder focusing can be a little fiddly with the XA and its small focus lever in the center just bellow the lens but it works.
Have you ever wondered why it can be so difficult to achieve focus on close subjects? Bellow is some of the Olympus XA’s depth of field at different apertures presented graphically.
The yellow area represents the closest and furthest distance that is reasonably in focus for any given aperture when focused at the minimum distance of 2.8ft. You can see that increasing the aperture does not have the same increase in depth of field as it would if the lens is focused at a further distance. Contrasting this when the lens is focused at 12feet an increase in aperture can have a dramatic impact on depth of field. An example is at f5.6 and 12feet the area considered to be in focus is from about 7.7ft to 27.5ft but simply stopping down to f8 yields 6.7ft to 62ft.
This is how fixed focus cameras work they are set to a certain distance of focus and an aperture that provides enough depth of field. Similarly this is what you are doing with zone focusing and again why that can be so difficult when you cant control the aperture and the camera to subject distance is short.
Olympus considers the XA as one of its technological milestones for its online camera museum. Olympus Museum Cameras XA
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.
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.
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
