Olympus OM-D: No low pass filter

This what I claim to be true. I have not taken an OM-D apart, though. I have only seen quite a few images.

Some time ago there was a "mistake" at Olympus France web site. They said in a spec line that Olympus PEN E-PL5 has no low pass or anti-aliasing filter. This spec line was removed and it was said that all Olympus bodies with Sony 16MP sensor are alike.

Before this incident I had not thought about LP filter in OM-D. I had noticed that it must be very thin because there is some aliasing and moiré time to time but nothing to be worried about. Also OM-D images are very sharp which also made me think that LP filter must be very thin.

I have used digital backs which have no LP filter since 1997. I went through my old images and checked the frequecies where aliasing and moiré can be seen and compared to them to OM-D images. One of my reasons to play with Nikon D800E was to check its files in Lightroom. While it is said that D800E has no low pass filter, techically it has some kind of a filter and it works a bit differently. So, I loaned a couple more new digital camera bodies which have no LP filter.

This image is an enlarged crop from an OM-D frame showing moiré patterns.

My conclusion is now: Olympus OM-D has no low pass filter at all.

Is it a good or bad thing then? No. It just is what it is. I was curious.

Moiré and aliasing are not problems in RAW files, and when moiré is present it is easy to be corrected with Lightroom tools. Only every now and then there is a jagged edge which needs some hand work. With JPEGs I have not seen any complaints at photography forums. 

So this is sort of a non-issue, but I thought to let you know... ;-)

-p-

Nikon D800E and Olympus OM-D

No, I´m not going to use both D800E and OM-D. This was just one of my reality checks. It is nice to check every now and then what´s going on with various brands and systems. I did not want have the subject as D800E versus OM-D because this also is not about that. There is no single camera of which I could say that it is made for me. There are a few cameras I could be perfectly happy with, if there were no other choices. Both of these two overlap my needs but differently, and I wanted to know to what extent and how differently.

Size matters

One of obvious differencies between these cameras is physical size and weight. The image above shows them with lenses which give (almost) equal angles of view: Nikon 35mm f/1.4 G AF-S and Olympus M.Zuiko Digital 17mm f/1.8. Both are the best native "35mm" prime lenses from respective brands for these bodies. 

The difference by 2X for focal lengths in these lenses shows that there is also the same difference between image size on sensor. The area of OM-D sensor is roughly one quarter of D800E sensor size. Respective sensor sizes in pixels are 6144 x 4912 pixels for Nikon (36 megapixels) Nikon and 4608 x 3456 pixels (16MP) for Olympus. Sensors have different aspect ratios, 3:2 for Nikon and 4:3 for Olympus. Because of different aspect ratios final images are cropped a bit differently and actual resolutions are dependent on this cropping. I would say that D800E has roughly 37% more linear resolution to start with when compared to OM-D. True relationship with image quality is dependent on many factors including filters on sensor, the lens and of course users´s shooting and post-processing technique.

Handling

I have used Nikon FF DSLRs long enough to be happy with D800E from the start. There´s "nothing" to it. It´s just like a Nikon should be. Olympus OM-D has become pretty much an extension of my right hand. D800E couldn´t become so much used because of weight and size. For me this is the difference, not handling as such but size and weight. Every extra lens makes the disparity only more favorable for OM-D.

This is the situation now. If I were still an advertising photographer I would go for more resolution and Nikon´s excellent 85mm PC-E lens. Nikon has also better AF tracking, but I don´t need it.

Camera Body Tests

I have tested and written about OM-D. Others like dpreview.com or dxomark.com have tested both. I will not go any deeper into that territory here, just refer to a couple of measurements later when they mean something.

Key West, Florida, USA, 2013. OM-D w. 17mm f/1.8 lens

Camera-with-Lens Performance

This is what I´m interested in. Final image quality with RAW images opened in latest Lightroom.

I posted in January a blog on diffraction. There D800E was my example for two reason: diffraction is easy to see because of huge resolution but also it is not such a problem as common "wisdom" says. I´m not going to duplicate those crops from image center here.

Here is my test targets as shot with D800E:

I shot the same with OM-D so that the subject ie. those targets take the same area of frame. Lets compare what happens in corner targets, which are far from extreme corners. 

Above is D800E 35mm at f/8 and below OM-D 17mm at f/4. Nikon D800E crop is 100% and OM-D crop has been enlarged to the same size. Why these apertures? Because that´s my most used depth of field and DOFs are equal when D800E is closed down two steps more than OM-D.

Now, check Nikon 35mm center performance in my previous post. The difference is quite obvious to what is seen here with Nikon 35mm lens. Even here D800E crop is slightly sharper or should I say cleaner than the enlarged OM-D crop but the difference is neglible for any practical need. There is a test of Nikon 35mm f/1.4 G lens at photozone.de. They tested with Nikon D3x. D800E only amplifies the difference between center and corner performance.

In this example ISOs are at 100 for Nikon and 200 for Olympus, these are studio shots on tripod. I shoot normally hand held. To keep shutter speeds the same I would need then to raise my ISO for Nikon to 800 if OM-D is at 200 in order to have same DOF. Actually this would not be a problem for Nikon in this kind of situation. ISO 800 suffers only slightly. The difference is even not worth producing here. What happens though is that D800E loses it´s lead in dynamic range, which can´t be seen with this kind of target. According to dxomark.com these two cameras would have practically the same dynamic range at ISO 200/800 setup. The same is true for tonal range and color sensitivity. The only real difference between these cameras with these lenses would be resolution in the center of frame. (Structures in grayscale is not sensor noise, this structure comes from printed target). 

Key West, Florida, USA, 2013. OM-D w. 17mm f/1.8 lens

In Print

I prepared print size files for you to print and see. Nikon crops are from the center of frame and, lazy as I am, OM-D crop is the same off-center as above. M.Zuiko 17mm has quite even performance over the frame. In print size A3 there is no visible difference in print between images or test target from these two cameras.

Also size A2 prints are quite similar with normal everyday subject, but with this kind of target the higher resolution of D800E (above) can just possibly be seen on glossy paper. It depends on printer, paper etc. Make a 6 by 6.1 cm and 300 ppi background in Photoshop. Copy and drop the above crop from A2 print file into it. Print with your printer. Any difference?

This is an image file for a crop from A1 print. Make a 6 by 8,7 cm and 300 ppi background in Photoshop. Copy and drop the above image file into it. Print with your printer. Any difference?

Real Life

Pixel peeping on screen and reading numbers on some test sites is easy. Knowing what matters in real life and what doesn´t (and how much or how little) is a lot harder. These examples above show that the absolutes are not valid in real life, and these examples are still far from real life and in favor of the one which has the better starting point.

In real life hand held photography there is one more thing which forces these cameras closer to each other. It is in-body image stabilization (IBIS) which OM-D has.

What we have here is again D800E above and OM-D below, but this time I´m shooting hand held in a dim light. Exposure for OM-D is 1/13 s at f/4 and ISO 200 with IBIS on. I can get sharp images with a ratio of 9/10. To get sharp images with D800E, I had to set shutter speed at 1/30 s at f/8 and raise ISO accordingly to 2000. Now my test gave me sharp images with a ratio of 3/10. Sharp and sharp... Well, this is what I get at these parameters. This goes to show the power of IBIS. Besides of sharpness there are other things to consider, at ISO 2000 D800E has fallen below OM-D in dynamic range and color accuracy. IBIS keeps you going within the sweet spot of OM-D for a long time.

Miami Beach, Florida, USA, 2013. OM-D w. 17mm f/1.8 lens

Summary

Technically, if you are striving for the most detailed images, Nikon D800E is far better than OM-D. It has more resolution, wider dynamic range and higher color accuracy. But then also you must be up to task because this goodness does not come for free for the careless shooter. You must use tripod, you must use only the best lenses inside their best performance envelope. Small things mean suddenly a lot if you want keep the performance up. On the other hand D800E has plenty. You can give away a lot and still get great images.

My D800 pluses compared to OM-D

- lots of resolution, dynamic range and color accuracy to start with

- better viewfinder in bright daylight

- possibility to have shorter DOF

My OM-D pluses compared to D800E

- size and weight

- IBIS helps keeping ISO low and dynamic range up

- better exposure metering (ETTR) with a practical gain of at least 1EV in DR 

If I were a hardcore dedicated landscape photographer or still an advertising photographer, I would take D800E. While I am not, D800E does not give me anything above OM-D in practical shooting and in my print range of A3 to A1. It would not make my images any worse either. It only is bigger and heavier and it would strip me from many shooting opportunities which a smaller system gives just by being smaller and handier to have with me.

-p-

OM-D Playground in Berlin

What would you think about a building which would contain lots of different themes with which to try cameras, entry would be free, cameras with memory cards would be given free to you to try at your own pace, there would be people to help you with settings if needed and you could take the memory card with your shots with you when you leave?

Hmmm... Sounds great? I think so, too. Actually there is such a place where you can play with Olympus OM-D. It is in Berlin (Germany) and it is called Olympus OM-D: Photography Playground. This playground is built in an old industrial building and it consists of interactive installations by nine artists and groups. The common theme for these installations is Space and Art.

Room with a perspective. Image: Veera Korhonen, vidastudio.fi

You can walk into installations and interact with them - and take pictures according to what is recommended or how ever you want to shoot it. Outside of every installation there is an explanation of the photographic and audio-visual experience the artist has tried to give you and the camera settings you should have to best shoot or video it.

OM-D Playground runs until 24 May at the Opernwerkstätten Berlin, Zinnowitzer Strasse 9. It is open daily between 11 am and 7 pm.

If you happen to be in Berlin before the playground is finally closed, I really recommend you to try this experience! And don´t hesitate to ask for other lenses than the 12-50mm zoom which will be attached to OM-D when they give it to you. With some installations you would like to have a tripod which you can also ask for. The total area you can wander in is around 7000 m2 and this old industrial interior probably inspires you to take some images also outside of installations. The idea is to have fun while exploring the playground and OM-D.

-p-

Some more images from the opening night:

Copying slides with OM-D and 60mm Macro

This is the promised follow-up article for my review of M.Zuiko 60mm Macro. I try to explain here quite thoroughly how I digitize slides.

This image shows my setup "in action". 

It all starts with OM-D body and the new 60mm Macro lens.

This metal tube is from a Dörr Slide Duplicator kit. Similar kits are sold with other brand names like Polaroid or Bower. Polaroid HD Slide Duplicator seems to cost USD 35 at Amazon.com. These kits consist of a metal tube plus film holders. They have also a close up lens which is meant to be used with a normal (i.e. non-macro) 50mm lens (100mm lens in FF 35mm format). The results from any combination of a general photography lens and close up lens are too soft. Not worth trying. Remove the close-up lens from its ring for some other, non-serious use... Dörr tube has 52mm filter thread which means that a step-up ring from 46mm to 52mm is needed. 

Next thing to attach is this frame for film holders.

There is a holder for two framed slides. Slides and negatives are shot with emulsion side to lens to get the best sharpness. You are looking at emulsion side when letters at edges are wrong handed. Framed slides should have darker side on emulsion side, but it is also easy to see that emulsion side has a slight structure when you look how light mirrors from the surface.

You can also copy un-framed slides or negatives.

The opening image shows how I shoot against a light box with even light surface. My light box is made by Just. They seem to call light boxes as transparency flat viewers. These boxes have an excellent light quality: 5000 K with very high color rendering index, CRI, at 98 (of 100). I set a captured white balance for the box. My OM-D reads the box to be 4990 K. For color negatives the WB must be set through the orange base mask. I expose using my ETTR method as explained in previous blogs. There is usually no need to do any bracketing. With color slides exposure time is usually around 1/5 to 1/20s at f/5.0 and ISO 200. My tests have shown f/5.0 to be the sharpest aperture with 60mm Macro at these magnifications. 

I open RAW files into Lightroom. First thing to do is to flip images horizontally. They are wrong handed because of shooting from emulsion side. Other than that slides need very small, simple corrections. Negatives are turned into positives in Tone Curve window. The linear point curve goes from bottom left to top right as default. It must be reversed to go from top left to bottom right. Save this as a preset. After turning negatives into positives they usually need some adjusting to get tonal values and colors right. A reversed Tone Curve makes also tone sliders to behave backwards. If this feels awkward you can always make an Export into TIFF file after reversing of tones and then import this file into Lightroom. Now sliders work normally.

The length of the metal tube dictates your focusing distance or magnification. I have two tubes, a longer one for a magnification of slightly less than 1:2 and another shortened for magnification of circa 1:1.2. With the former I can capture 35mm slides or negatives as one capture. The latter one gives more pixels and resolution as the slide is shot as four quadrants. An easy way to make different length tubes is to use empty filter mounts.

 

This image shows how much overlap my system gives. It helps me to be fast and make combining quadrants easier for Photoshop.

I choose the four quadrants in Lightroom and use command Photo > Edit In > Merge to Panorama in Photoshop. Photoshop automatically opens these four files with Lightroom tweaks and combines them into a seamless image. This image is saved in Photoshop and it opens automatically into Lightroom. The process is quite fast and easy.

The combined image before final cropping. Dimensions are now 7789 x 5142 pixels and the quality is better than with any scanner except drum scanners. I have owned them all, drum scanners, Flextights, Nikons...

100% or 1:1 detail from the above image. The grain you see is film grain. I get it sharp from edge to edge, and there can not be any details beyond sharp film grain.

-p-

Update on November 26, 2012 at 14:59 by Pekka Potka

Update: Some more information

I measured a few usable tube lengths with my Dörr duplicator, which is the same as Polaroid or Bowens. (Note: These gadgets might not stay the same for ever. So there may be some variations with tube lengths...)

First I have a Heliopan step-up ring 46 to 52mm. It adds 4mm. The frame for film holders (as I call it) adds 10-12mm more beyond the tube depending on film holder and/or slide frame used.

To get the whole 35mm film frame with one capture I need a tube of 112mm. To make the film frame fill OM-D sensor (cropping the longer edges) I need a tube of 102mm. To copy film frame with two captures I would use a tube of 90mm. And for four captures I use a tube of 72mm.

I have one tube which is shortened to 72mm. An easy way to get all the other lengths is to use empty, round filter rings, i.e. filters without the glass. Companies like Heliopan sell those and also you can find cheap used filters from shops selling second hand equipment. Just smash the glass with hammer or open the locking ring, depending on how you approach pimping. Duplicator kit includes close up lens, remove it from barrel and you have a long adjusting ring. Here I would go for opening the locking ring... This barrel plus four empty filter rings is all I needed to get all the above mentioned lengths.

The frame for film holders can be moved up/down in plane and film holder can be moved right/left. That´s how you get the four quadrants. I have printed single-capture images as A3 prints and get them with beautiful, sharp grain and crisp, nice details with 60mm Macro/OM-D combination. I would say that copying film in one capture either fitting into or filling (with slight crop) the OM-D sensor is good  enough for "normal" images. Using four captures and combining them afterwards is only needed for the sharpest images where you absolutely want to be sure to copy them as well as possible.

Color negative has this pesky orange mask. Also there are lots of variations between mask colors and densities with different film brands. The quick and dirty way is to measure WB as said in original text and then use a blue filter, say 80B jsut like Jose Luis suggested above, in front of the duplicator, between light and film. Setting WB in Kelvins might help here, too. The rest can usually be taken care of in post processing. Color negative is so flat that it needs tweaking always. However, the best situation is to have a clear piece of color negative film in place of image when you set WB. If the film is clipped too tightly from the beginning and end there just might be not enough clear ares even with the longest tube length. 

Someone said that slide holder is good only for thin frames. The holder in my kit is tight but even thicker frames go in without extra power. I only need pliers to get frames out...

This same basic copying technique works for bigger film sizes. I only don´t know any similar duplicators for them. Handy people build them quite easily I think. Various film holders are sold as scanner accessories. I copy my 120 size and sheet films without any kits. I have light box flat and level on table and camera attached to a small tripod above it with the lens pointing exactly right down on light box. Moving film holder is easy and there seems to be plenty of DOF at f/5.0. The important thing is to mask all extra light off (e.g. with black cardboard).

-p-

Olympus E-PL5 beats OM-D hands down! Or?

The internet and the truth, oh well! Sharks swimming in hurricane Sandy´s flood waters at somebody´s backyard. Wow! Olympus E-PL5 having one stop more dynamic range than OM-D. Wow! Olympus E-PL5 having no low-pass filter. Wow! I´m really not speaking here about hurricane damages and some digital cameras in the same context but wondering about the dynamics of the internet. How one post in the internet can cumulate into something big, worldwide and very true. There were sharks swimming in many places, like in flood water among running cars, already during hurricane Irene. So, it is only natural that from now on we see sharks swimming in peculiar places when ever there is a flood.

Blatant faking of reality is of course one thing and honest (miss-)drawing of conclusions is another. Which leads into these two cameras. E-PL5 is the newest in PEN series from Olympus. According to Olympus it has same sensor and same processor and same image quality as their flag ship mirrorless, the OM-D. But, as you know, camera factories simply are not reliable. We have already one test showing that E-PL5 has one stop better dynamic range than OM-D. Also we have now information that E-PL5 has no low-pass filter (while OM-D has). And both facts are circulating the internet as - yes, as facts. 

Olympus (like others) has been developing their anti-moiré algorithms all the time to make ever thinner low-pass filters possible. That´s good for image sharpness. Already OM-D has a relatively thin low-pass filter and the importance of algorithms is easy to see if you convert an OM-D RAW file in Olympus Viewer 2 or Adobe Lightroom 4. Viewer 2 software removes moiré nicely while in Lightroom you need to do manual corrections quite often. Viewer 2 gives also an option to leave anti-moiré off. Also all the other parameters can be set exactly the same. This gives us a great possibility to compare these two cameras which have same sensors but the other is with low-pass filter and the other with none, presumably. The difference should be obvious and it is seen below.

Doing tests is difficult because you have to be sure that what you get is what you were after. That´s why I usually even do not show those vertical lines in my reviews . They are more sensitive to the slightest differencies in camera or sensor angles than anything else. Here I know the slight difference we see in them comes from changing the camera, or maybe the sensors in these two individual camera bodies are not absolutely perfectly aligned when compared with each other. Other than that, the only thing we can see in these two images is that there really is no difference at all. Yes, there are very, very slight differencies but they can come from so many little deviations. What I can say is that there is a similar low-pass filter in BOTH cameras or in neither. The former is true here. Actually it is quite amazing that these two camera bodies, one OM-D and one E-PL5, produce such outstandingly similar results! And that is the only thing which surprised me. Tolerancies in making these cameras must be very small.

Okay we have now busted one myth, unless I faked these test target images, of course ;-)

The other claim was that E-PL5 has a one stop advancement in dynamic range over OM-D. I shot this same test target to see dynamic range over a range of 14 stops. Neither of these cameras do not have such a range, of course. I only wanted to be sure. Again, the results were just alike as above. Every pair of similarly exposed images is just as close to each other as above. There is no difference in dynamic ranges between these two cameras. And that´s it! 

-p-