Take the Photo When You Want

This must be a generation thing... I heard about "shutter lag" first only a few years ago. At that time, I had a hard time understanding what the actual problem was. Mind you, my photographic experience originates in a fully manual SLR-cameras, which always released the shutter when I pressed the release button.

Finally, it all was clear to me, the complaints about shutter lag was caused by fully automatic settings, in particular auto-focus, of "modern" generation automated photographic equipment.

Being used to manual focus, my habit was to set the cameras to all manual, in particular for focusing. I never trusted any camera to know what I wanted in focus.

Lately, some cameras had a real impact on me, cameras that could be told which distance to focus at and stay at that distance.

First to mention in that context is the Fujifilm X-Pro1 with adapted legacy glass. Some of my older M42 lenses are rather sticky in the focus department. Set the lenses' apertures to f/8 and adjust focus according to the distance scale. Done! The metering of the camera is fast enough to adjust the shutter speed in an instance. However, if one wants to be rally be assured of the fastest reaction of the camera: choose ISO and shutter speed (according to sunny 16) manually. Great to have a dial for shutter speed selection.
The camera should have lost all the shutter lag by now.

Second choice: Ricoh GR (version V) or GR-II. Ricoh understood that auto-focus causes the greatest delays in automated photography. So, Ricoh decided to add the "snap focus distance" feature to their GR camera. With the camera in AF mode, half-press the shutter release and AF will start. However, when focus is not yet achieved but the shutter release is fully pressed, the focus defaults to a predetermined distance. Brilliant! Again, depth of field by the aperture chosen helps to determine the preset zone.
The Ricoh GR is extremely compact and fits in pockets, however, operation is very much menu-based.

Next: Leica X2 (Leica X-E, same camera, different color scheme). The Leica allows for decent manual zone focusing. The focus distance can be locked in, so it can't accidentally knocked off. That is really great for zone focusing with a predetermined DoF. The Leica also offers manual aperture and shutter speed dials, which is great for fully manual exposure settings.

Only at my 4th place: Fujifilm's X100 series. I love those cameras, no doubt! The manual focus scale displayed in the OVF is magnificent. However, the focus ring is very loose, I knocked it off bu accident several times, which ruined the shots. I wished there was a feature to lock the manual focus.
The X100 series sports manual aperture and shutter speed dials, which is really great!

5th (1st) place, solely for the reason that the other cameras are doing so well when stabilisation is not required: Olympus MFT bodies. Those cameras employ in-body image stabilisation, which is great for low light situations. When in any low light environment, the Olympus OM-D E-M5 is my prime choice! With adapted legacy glass, the Olympus still stabilises the image by sensor motion.


The above ranking is certainly not carved in stone! The differences are pretty subtle.

The most important message I wanted to convey:

1. shutter lag exists when shooting in AF
2. shutter lag disappears almost completely when focusing manually
3. setting exposure parameters manually cannot harm

Conclusion: Remove as much automation as you are comfortable with, you'll be rewarded with a more timely photography.

Vintage Lens - Rapid Aplanat f/8-f/64

The vintage 13x18 (cm) camera, I recently bought of ebay seemed to have suffered from moisture a lot.
While the camera is still ok, the plate holder is really warped.
The lens (Rapid Aplanat) was also suffering from the moisture too, having developed severe fungus. Have a look:

front view

rear view

The lens can be taken apart, in the same way as many other larger format lenses: the front and rear groups can be screwed of the lens barrel.

the lens taken apart

one of the groups

The barrel still retains the iris. In my case, the iris was really stiff. Cleansing with several passes of lighter fluid, followed by some petroleum jelly and more lighter fluid, seen to have loosen up the iris sufficiently.

the diaphragm at f/64

Pictures of clean lenses are boring, hence, I decided to not show any.
I wiped down the front and rear surfaces of the front and rear groups with alcohol using fresh a q-tip for each of the surfaces. Said wiping down is to be performed in a meandering fashion, starting from the middle of the lens.

My Rapid Aplanat is now as clean as clean can be. There are no visible traces of the fungus left.

Next step: make a plate (film/paper) holder.

Big Boys Go Modern

As a frequent reader of my blog, you might have noticed that I am into trying/doing the unusual.

Here's my trick to adapt the mirror-less camera with the worst reputation ever (not justified in my mind), the Canon EOS-M to my Plaubel PECO Supra large format view camera.

Before going into any details, let's have a look why anyone would want to do that...
Large format cameras can provide a unique look, with all the possibilities of raise/fall, shift and tilt in many direction.
Today, when you are lucky, large format cameras come really cheap. So do their lenses, in particular when the shutter is not functioning properly anymore.
Here's the good thing, when using a modern digital back, be it a DSLR or a mirror-less camera, the shutter is in the camera, in front of the sensor. (Well in most cases at least, known exception: Pentax Q). So, we don't need a functioning shutter for the following project: Add a digital camera body to a large format camera.

For my approach, this is what you need:

A lens board for a Copal #1 shutter

Copal #1 lens board

M42 macro rings, 1 short, 1 long

M42 macro rings

Adpaters for T2/EOS and EOS/EOS-M

Canon adapters

The short M42 ring mount to the inside of the camera (see photo below), while the longer ring counter-screws on the outside. 

Assembly

In the recessed lens plate

Camera attached

Front side view

Here's the catch: M42 and T2 are not exactly the same threads. Don't apply any force! Your T2 adapter will be destroyed.
A regular M42/EOS adapter is too short to clear the camera from the recessed lens board.
Here are 3 options:

1. get another M42 macro-ring
2. get a non-recessed Copal #1 lens board
3. fabricate a Copal #1 lens board

It might be easiest to actually make Copal #1 board from a sheet of aluminum...
For now, the setup works just fine, although I do prefer using large format film with my large format cameras.

The Q-code

Hi there, sorry for the misleading title, this post is not about amateur radio, this still is about my photography adventures.

Coming from SLRs, I had severe doubts about the use of mirror-less system cameras. Yep, past tense, since the purchase of my first digital system camera, the Canon EOS-M my appreciation for mirror-less digital cameras changed. What triggered my initial interest was that the EOS-M employs an APS-C size sensor and no mirror to flip up and shake the camera. ("Haha", I here you thinking, "mirror, no mirror, what is this guy all about"). The initial plan was to mount the EOS-M behind a decent telescope, for astro-photography (makes sense now?). Whatever the EOS-M's reputation is, this is a very good camera, not only for video, but also for stills, despite the slow auto-focus.

From there, I moved down in sensor size (MFT aka m4/3), by getting an Olympus PM-2, which I love a lot.

Now my interest for mirror-less cameras was ignited.
Following the scene, it did not take long and I was intrigued by Pentax's Q system. Sooooo small! Well, also the sensor. Hence, I had my doubts, and stayed away from the Q.

And now, it struck me, the Q has got no mechanical shutter in the body, the sensor is back-lit, the firmware has got a built-in intervalometer and there are plenty of adapters available (including T2).
For astro-photography, the Q system might just be the thing!
Also, the Q-system sports in-body "shake reduction" by sensor shifting, allowing for manual/old lenses to be used with image stabilization.

So, I got one.

Now, out and about, I learned to love the Quirky little camera. Small enough to fit in any of my coats, including a wide arsenal of lenses.
Concerning which, I presently own the following genuine lenses:

• 01 - standard prime (8.5mm f/1.9)
• 02 - standard zoom (5-15mm f/2.8-4.5)
• 04 - wide toy lens (6.3mm f/7.1)
• 05 - toy tele-lens (18mm f/8)
• 06 - tele zoom (15-45mm f/2.8)
• Holga lens for Pentax Q (10mm f/8)

Some of the genuine lenses are supplied with a lens internal leaf shutter and a neutral density filter. Of course you know what that means... using strobes or speedlights at very fast shutter speeds.
When using lenses not equipped with a shutter, e.g. legacy glass of the toy lenses, shooting is entirely quiet, due to the electronic shutter. On the downside, the electronic shutter can be used up to 2s only,

By now, I also own a Q7 body. Despite the Q and the Q7 bodies have the most recent firmware, there are remarkable differences.
While the Q seems to handle a lot more easily, the Q7 got some feature I really miss on the Q.


Advantages of the Q

• metal body, creating a very balance experience
• intuitive dial customization
• stereo audio in video recording

Advantages of the Q7

• bigger sensor
• records RAW when using smart filters or effects
• slightly elevated buttons

There are probably more differences, but those are the ones that struck me most.

To me, it is impossible to pick a winner between the Q and the Q7. Although, the Q gets out a lot more often, probably because of the balanced feel of the metal body camera.

Another thought about the Q-system: C-mount lenses, which will fit the sensor just fine and can be really inexpensive.

Should you get a Q or a Q7? Well, I don't know! Just don't get a Q10, which is just a Q in a plastic body.

Focus Peaking on Olympus Digital Cameras

On the search for a second body for my m4/3 system, I came along some hints on how to simulate focus peaking of Olympus cameras not being provided with said feature.

Research on the wides of the interwebs revealed that apparently a contract between Sony and Olympus prohibited the latter to include focus peaking on sensors made by the other party... remains to be confirmed actually.

However, there are clever people out there, which figured out ways of using "focus peaking" with Olympus' cameras. As a straight RAW-shooter, personally I would never been able to come across such a simple solution!

Olympus added some nifty "art modes" for JPEG images.
Here is a video making use of one of said filters for pseudo focus peaking: click! Amin explains how an OM-D can be set to perform this function. However, there is one thing I would like to point out, before you follow Amin's instructions, set the camera to MF (manual focus), otherwise, AF (auto focus) will be assigned to the function button.

When moving towards a slightly different camera, the PEN Mini2 (E-PM2), things change slightly.
Here is what I did, which should work on most Olympus cameras.

• put the camera into manual focus - not required when using legacy glass
• set the camera to record in RAW and low resolution JPEG
• engage the art mode 11 - "Key Line" (filter 2)

All you got to do is focus such that black lines will maximize at the intended focus area and snap a shot. Chimping your shot, you will see the artsy stuff only. Don't worry, on the memory card, there will be 2 files, one artsy fartsy JPEG image and a RAW file, the latter containing the image you wanted.

This is the very famous "filthy apple keyboard" image, used for similar purposes by so many others... Mine is taken with an Olympus PEN E-PM2 and a Cosina COSINON 55mm (@ f/1.4). Have a look:

Key Line art filter image saved as JPEG

Filthy Apple Keyboard image saved as RAW

The art filter enabled, the camera's live view, back screen of EVL, will show the art filter, thereby imitating focus peaking.
Concerning file sizes, the artsy auxiliary file is 292KB, while the RAW image file is 13.7MB.

There you have it, focus peaking with the E-PM2.

Body Shopping Part 2

The micro four-thirds, m4/3 or MFT for short, system is increasingly popular. And of course, in the beginning of this year, the MFT-bug bit me too. For my needs, I figured an Olympus PEN E-PM2 would just be the apparatus to have. After some months, there is nothing that I would regret about this purchase! I love its point & shoot appearance and the silver color, pretending to be a somewhat lower end pocket camera, in particular with one of the body-cap-lenses fitted.
The regular reader of this blog might have seen some pinhole, body-cap-lens and other experiments coming along, which not only create interesting results, but also provide me with a lot of photo fun, which, of course, is why I am busy with photography in the first place.

Right, the title says Body Shopping... and this is exactly what I did today! Yep, I bought a second m4/3 body.
It was always one of my plans, once that I liked the E-PM2, to add some more advanced features.
My considerations were going back and forth between Panasonic and Olympus. In terms of models, that would have been the GH3 or GX7 on the Panasonic side of the game and the E-M10 or E-M5 in the Olympus quarters.
This pre-selection was mainly triggered by the availability of controls and the presence of an electronic view-finder.

In terms of pricing,  any of the above mentioned camerast are all pretty close, however, concerning features, anyone of said cameras provides a set none of the of the others comprise.

I got a portrait grip for my DSLR, which I like a lot, both actually, the DSLR and of course the portrait grip. Not only does the grip add battery-life and also prevents "The Broken Chicken Wing".
The option of having a grip with an extra shutter release button for vertical shooting removed the GX7 and the E-M10 from the short-list. While there is no additional grip for the GX7, the grip available for the E-M10 does neither have an additional battery, nor and extra shutter release button.

Going into the third selection round, one camera fell off. Owning a decent collection of legacy glass, in-body image stabilization seems a good thing to have, thereby eliminating the GH3 from the short-list.
Not so fast, I hear you screaming, what about the E-M10, having IBIS?! And there is one feature, speaking of legacy glass, the E-M10 has an advantage over any of the bodies on the list: focus peaking.
Is it a fight between the E-M10 and the E-M5 now? Focus peaking vs. battery grip?
To be honest, this had me thinking for a while. In particular since the pricing of the two bodies is very close these days. It seems that other features of the E-M10 attracted a lot of buyers, while the 2 year old E-M5 appears outdated to many.
Speaking of the E-M10's additional features, most seem really interesting for most folks, e.g. WiFi, HDR and other things of this nature. I like such features too, however, Samsung NX300, which I won recently, can connect to WiFi and do some tricks on tablet PCs, however, after having tested these facilities, I never actually used those in real photo-life. Concerning HDR, which I use occasionally, I prefer to have full control and rather create the final image manually.
Hence, the battle is between the battery grip with shutter release in verticals against focus peaking (for legacy glass)... or is it?!
This video partially pulled me over to the original OM-D, the E-M5: Pseudo Focus Peaking with the OM-D (a similar trick works for the Olympus PEN E-PM2, will write this up later, stay tuned!).
The final push was that a photo store next town (Rotterdam) offered a free Olympus HLD-6 battery grip to any OM-D E-M5.

=> The decision was taken! I reserved an Olympus OM-D E-M5 body for pick-up for €799.

And now things to really interesting and exciting! When I arrived at the shop, the very friendly employee (big cheers!!!) told me that the camera, when bought in the store, was €699.- only and offered me to sell it to me for this price, despite the earlier commitment from my side. Wow, that's what I call service... thumbs up (FOKA)!

Concluding, not only have a gotten all the features I was looking for, thanks to Amin Sabet, but also got a great deal on the camera (-€100) and a free HLD-6 (worth €200+). Wow! What a day!

The Gods of photography blessed me today!

Big THANKS to the Gods and FOKA!

To Infinity and Beyond

Again in a adventure using really cheap lenses. This time I went CCTV-style, using very a very in-expensive C-mount Bokeh-monster.

Concerning the title, this lens, mounted on a m4/3-camera, using the appropriate adapter, will actually focus at infinity, and even beyond (which is of no use what so ever).

Setup
Have a look, here is my Olympus PEN E-PM2 with a 25mm f1.4 CCTV-lens

Olympus w/ VF2 and 25mm f1.4 CCTV lens

Yes, this does look ridiculous, I agree, however, the EV (electronic view-finder) make focusing so much easier... highly recommended! And yes, the lens look kinda out of proportions.

CCTV-lens on Olympus E-PM2

Some words about the 25mm lens. There are several models available for cheap from the Far East. When browsing evil-Bay, you want to make sure to get a good one, or let's say, the one you really want. On youtube "Blunty" reviewed a CCTV-lens with a rather poor iris, which went from odd to square when stopped down. It seems that this lens employs an iris having 6 blades.

Contrary to Bluty's lens, I ordered one, on Evil-Bay, which was mentioned to have an 12 blades iris. And guess what, the lens that was sent to me got 12 blades in the iris! So, if you are looking for consistent bokeh, pay attention to which lens to order...

Pics

Now, let's dive into some pictorial goodness...
Very much like the lensbaby stuff, the CCTV-lens has some sort of a sweet-spot, which can be controlled by the iris, hence the importance of having a homogeneous iris in the first place.

25mm @ f1.4

25mm @ f4.0

25mm - closed as much as possible

Right, technical stuff done, what about real files?
Don't know what drove me to take picture of moving subjects... the manual focusing with this lens is really sublime, i.e. very slow. Good for getting the focus on stationary subjects.
Although sheep are not belonging to the group of fastest creatures of the world, they gave me a hard time getting focus, lens wide open.

sheep running - f1.4

This little fellow was storming towards me from meters away... no chance getting a picture.
Then, close to the fence, he started to browse, however, he was moving is head sideways in a very fast pace, making it nearly impossible to get a good shot. Below, that's the best I could do... with a fully manual lens.

f1.4

Moving to more stationary subjects, what about some flowers?

Flowers @ f1.4

The shot above clearly shows the sweet spot effect of the CCTV lens. Still, this is just a regular shot.
In the next photo, I went a close as I possibly can, i.e. some sort of "closest up possible".

Minimum focus distance, f1.4

The following 2 images are HDR... for all you haters. For taking 3 shots, I had to stop the lens down, since it was impossible to get an underexposed frame with the lens wide open... and there is not ND-filter in the PEN-Mini2.
And yes, I used photomatix, for styling too. Argh! Should be a no-go, according to many photographers.
Anyway, here is what the results are:

Sundown HDR, stopped down CCTV lens

Sundown HDR, stopped down CCTV lens

Summary
CCTV-lenses are interesting, inexpensive alternatives to rather expensive micro-4/3 system lenses.

There are some down-points to such lenses:

• Those lenses look really quirky on an actual m4/3-camera.
• They create severe vignetting, when stopped down entirely the vignetting is beyond being acceptable. 
• Wide open the focus falls into a sweet spot rather than a decent focus plane.
• f8 seems to be the limit of stopping down the lens decently.

On the positive:

• Those lenses are really inexpensive.
• The Bokeh, using the right lens, is beyond any available pro-grade (D)SLR-lens.
• The low-light performance is exceptional.
• C-mount lenses are really small, not filling up the bag.
• Focus action is really slow, making it easy to focus w/ the aperture wide open, provided the subject is not moving too fast.

Summing up, C-mount lenses are worth the consideration. There are some legacy specialty lenses available for this format... certainly worth to have a look at.

Legacy Glass on the Samsung NX300

Fortuna - Lady Luck, decided to bless me with a digital camera by means of a Dutch brewery presenting me a Samsung NX300.
Well, I like Samsung, my stone-age TV was made by them, and the 5" tablet (WiFi only), which usually accompanies me on trips, substituting a notebook computer. But, the cameras? Really?
In a local electronics store, I fiddled a bit with Samsung's P&S-cameras, however, I was not impressed, to say the least.
And now, I won their top-end CSC (compact system camera), the NX300 (top-end to the time at least, now there is the NX30, I know).

First impressions showed an all in all OK camera, but not more than that. Images of decent quality, however, there is a problem when shooting in RAW, which of course is my format. On the very left side, there is a stripe exposed about +1 Ev brighter than the rest of the image. When saving both, a RAW and a JPEG, in 80% of the cases the JPEG is cropped such, as to make the stripe disappear. Not sure what that means! Is it just my camera, or does Samsung actually know about the "feature" and hence crop it out of the JPEG?! I consider sending a mail to Samsung in order to get an opinion on what's going on here.

Well, this post is now about the flaws of the camera, it is about its strength!

Even before the camera was delivered to me, I purchased an M42-NX adapter on the interweb, since I own a fair amount of good quality M42 legacy glass.
The looks of the adapter were promising... However, sometimes, looks are deceiving. With the adapter installed, the camera told me that no lens was present. Hmmm, that was not according to the plan!
The wisdom of the interwebs suggested that using cheap mount from the far east may result in this error message. Well, I thought, let's invest 3x the money and buy an adapter made in the first world... same result! Money down the drain, mainly because I did not research the problem properly but trusted some auction-site's sellers promises.

It turns out that there is a switch in the camera, which a correctly mounted lens depresses, indicating the presence of a lens. Have a look:

NX300 lens port

Marked in red, this is the switch, which has to be depressed in order to indicate the presence of a lens.
The green mark indicates the lens locking pin.

For whatever reason, the adapter are not sufficiently thick to actually depress the switch far enough. Some guy on the interwebs deformed this adapter... I choose to stick some tape on it.

Aftermarket M42-NX adapter

Note the black tape used to thicken the bayonet. The red mark indicated the location of the switch sensing the presence of a lens.
Here, the green mark, just for orientation, highlights the recess for the locking pin.

With the tape added, the adapter was recognized as a lens. Perfect!

Now to the main attraction of the NX300, focus peaking! And yes, you guessed it, at first it did not seem to work. The camera was taking pics w/o any problem now, but there was no focus peaking or focus zoom by the usual suspects, e.g. shutter release half-press.
However, the wisdom of the ever mighty interwebs revealed that pushing the camera's "OK" button, starts whatever manual focus aid was selected in the config-menu.

There we go... Finally the entire camera makes sense to me!

For street photography, lenses can be manuallyt pre-focused on a 3m distance, which will provide a usable depth of focus of about 2.5m to 4.5m @ F8.

For portraits, the camera's focus peaking allows for very wide open lenses, such a the TOKINON 55mm F1.4, which is very hard to use on a dSLR.

Finally, to the beauty of it all. My NX300 came in black and silver, very classy, very stylish. Actually, some guy asked me about details of this camera, just because of its looks.
I happen to own some legacy glass in just that color scheme, e.g. ISCO - Westanar or CARL ZEISS - Tessar. Adding such lenses to the black NX300 makes for some real nice retro style gear, which is actually performing real good.

Samsung NX300 with ISCO WESTANAR 135mm

The Perfect Portrait Lens for MFT?

About this lens, you have seen me writing previously, the Cosina COSINON f=55 F=1.4 M42 screw-mount lens. These lenses are presently on Ebay for really really cheap. I wonder if people actually know what they are selling. Actually I bought 2, just because... well, not really, one for photography, one for astro-photography (check out my bellow-cam, somewhere in this blog).

So, this is how the lens looks like:

Cosina COSINON 55/1.4

You're probably not so much interested in how the lens look , but rather what the importance of such a lens is in the digital motorized auto-focus zoom era.
Well, with some cameras, manual focus can actually be quicker than auto-focus. As to zoom, walking back and forth, given the environment allows for this, is of course slower. Additionally, to compress the background, a lens change has to happen.

On the positive, this lens set me back about €30,- only. For an f/1.4, that is nothing! Right, to make it work, e.g. on the Olympus E-PM2, I had to invest some more dough to get myself an adapter. However, those adapters can be found on Ebay too, where they are shipped from the Far East for free (provided one is patient enough).
The adapter M42-MFT (micro four-thirds) came by mail today. Hence, the possibility to mount the COSINON lens on the Olympus PEN mini2 for the first time.

Due to the lack of a model, I took a portrait of a brick in a wall of my house.

 

scaled brick portrait @ f/1.4

Nothing done to the image other than converting from RAW to PNG and scaling it down.
Have a look at the nice bokeh in both, the foreground and the background... and this very shallow island of sharpness cutting through the frame.

Speaking of, this is a crop of the center line, in original resolution.

center of the image, original resolution

Yes, there is some color fringing going on. As I said, there is no "correction" applied whatsoever.


Now to some technical details, some of my readers are potentially interested in.

The focal length of about 55mm would be referred to as a "normal" when used on a full frame camera (36mm x 24mm), since this is essentially how we see.
The MFT's (micro 4/3) sensor size has a crop factor of about 2. Meaning the field of view on such a sensor would be equivalent to a field of view of a 110mm lens on a full frame sensor.
110mm equivalent falls spot on the realm of portrait lenses, because such a focal length gives enough background compression and still allows to be relatively close to the "subject".

In terms of brightness, we loose two stops! Meaning, mounted in front of an MFT sensor, the lens is now acting as a 110/2.8, relative to full frame gear.

However, there still is a difference between a 110/2.8 used on full frame and a 55/1.4 used on MFT, and an important difference that is! The depth of field!
The depth of field is only dependent on the distance between the lens and the sensor, i.e. the focus distance. Although less of the light that went into the lens from the object side is actually falling onto the sensor (essentially a fourth only), the focal condition did not change at all! The ratio of the distances between the object and the sensor are identical, disrespectfully of how much light falls onto the sensor integrally.

It seems there is a disadvantage of loosing two stops of light.
I don't think so! In portrait photography, we have control over all our light(s). In a studio, we will just have our (three) speedlites at full power rather than quarter power. OK, some recycle time is lost here...
In bright sunlight, there is even an advantage. How often did you experience that you had to use a 3 stop neutral density filter to be able to shoot wide open (depth of field)?! You might have even missed the shot, due to a lack of a neutral density filter, when metering resulted in s/2000 @ f/11 when using ISO 50. There goes your Bokeh! OK, in this example, loosing 2 stops will get us to f/5.6 only, still a little on the deep side, in terms of depth of field. However, adding a 3 stops ND-filter here, will enable us to open to f/2.

Yep, that was a little technical... I admit!

Confused?!

Maybe mathematics will help. Photography has a lot to do with mathematics! I will backup the following statements by suggestions to experiment you can perform with your very own DSRL.

When the focal length of the objective is doubled, the subject's image will be twice as tall/wide on the sensing surface.
Experiment: Set the zoom of your camera to 25mm and place yourself such than an object fills the viewfinder left to right. Now change your zoom to 50mm. You will see that one half of the object now fills the viewfinder left to right. => a factor of 2 in zoom leads to a factor 1/2 in one dimension of the field of view.
That means that the same amount of light is now spread on twice the width.
That also means that the same amount of light is spread on twice the height!
Therefore, a single pixel of a sensor will only receive 1/2 x 1/2 = 1/4 the amount of light, i.e. 2 stops of light.

What the depth of field is concerned, this is a 1-demensional entity, since this is only determined by the ratios of lengths along the optical axis. This dimension, however, is perpendicular to the dimensions (width and height) of the sensor. Thereby, not being influenced by the crop size whatsoever.
You may want to perform a boring experiment with focal distances, object distances and f-numbers... I would not recommend this. It's linear, hence, the changes are less visible and the entire exercise seems a bit boring to be honest.


There you have it. A very cheap legacy lens, bough from the interwebs, can be very convenient when used with modern digital cameras.

Heavy Metal for Bokeh!

New glass, well, old glass, new however to my collection of lenses, arrived today.
For not too much, I was able to obtain a COSINON 55mm F=1.4 lens, made by Cosina. Just for the sake of completeness, this lens has got an M42 mount.

Two different plans for this lens: 1) digital photography with the EOS M or the EOS 350D, 2) astro photography with the "bellow cam" webcam adaptation.

Concerning the first plan, of course this will be all manual. Remember the M (manual mode) and metering for exposure?

- With the EOS 350D, this works like charm. The front selector next to the shutter release sets the shutter speed, aperture, old skool, at the lens' aperture ring. Focusing with the 350D is a bit tricky. It seems that the light paths to the sensor and through the viewfinder are not matched in the entry level DSLR, hence, the focus on the sensor is a bit closer than the one in the viewfinder. The very shallow depth of field makes it therefore difficult to get sharp images right away.

- As to the EOS M, in manual mode, the selector wheel at the back can be set to shutter speed. Since there is no mirror involved in the M, focusing is really easy. Due to the shallow depth of field, you can literally see the focus rolling over the sensor.

Of course, both cameras employ aperture priority, just in case you are tired of metering.

With both cameras, the center of the old lens shows beautiful circular bokeh. Moving towards the edges, of course, this get a bit distorted...

The second plan, the bellow-cam, my bellow-cam. This is a QuickCam QC4000pro, modified for long exposures, see earlier posts on this blog. The macro photography bellow is actually designed for M42 lenses, hence the F=1.4 lens could be a very good light collector.

Of course, the also in plan B for using the lens together with the EOS M for wide-field astro photography.