Comparison between the Olympus MZD 25mm f/1.8 and 45mm f/1.8

Wait... What focal length is that again?
Although I am far from any sort of laboratory environment and offshore on a boat, I wanted to write about some of the differences between the Olympus 45mm portrait lens and its younger 25mm brother. This is my first attempt at a comparison review but while planning, shooting, and writing, I tried to put myself in the shoes of someone who was torn between purchasing one of these two lenses. They are an interesting pair in that they share a similar design with 9 lens elements in 7(25mm)/ 8(45mm) groups. When I heard that the 25mm f/1.8 was modeled after the 45mm, I knew it was going to be excellent and so far I have not been disappointed. So how do these two lenses perform side by side? Does their variation in focal length have much of an impact on real world use? For portraiture? As a macro alternative? Read on to find out =)

Focal Length


The 45mm f/1.8 has an effective (in relation to 35mm full frame) field of view equivalent to 90mm when taking the 2x crop factor of the micro four thirds system into consideration and was Olympus' first fast aperture portrait lens. After using the M. Zuiko 50mm f/1.8 legacy lens and enjoying this focal length, I went ahead and purchased the 45mm for its autofocus capabilities. Even though I really really really enjoy this lens there are times when I wished it was wider, especially when visiting places like Disney World. The 25mm f/1.8 fits this bill as it has an effective focal length of 50mm, meaning it captures about double the field of view (FOV) compared to the 45mm. OK, but what does that really look like? Below are three comparisons of what to expect in terms of focal length differences. In both instances my camera was in relatively the same position, but I was working handheld so there is likely some small error here. I was shooting manual to ensure that the camera settings between the two shots were the same and post processing was done using the same presets in Lightroom 4.
  • Barrels
45mm, f/1.8, 1/180 sec, iso 200
25mm, f/1.8, 1/180 sec, iso 200

  • Geowave Voyager

45mm, f/4, 1/350 sec, iso 200 
25mm, f/4, 1/350 sec, iso 200
  • Chain 
45mm, f/1.8, 1/125 sec, iso 200
25mm, f/1.8, 1/125 sec, iso 200
For any of these cases results between the two focal lengths are good. The images are sharp, bokeh (in the first and third images) is pleasing, and I had no problems using the same composition between the shots. However, I like the 25mm rendering better in the "Barrels" example because it provides more context to the photo ("hey, there are a ton of barrels here") and the 45mm for the "Geowave voyager" and "Chain" examples because the longer focal length really closed in on my subject. If you are having difficulty deciding between these two lenses, it really comes down to shooting style and working distance from your subject. The 25mm would be better suited for situations where you find yourself in confined spaces, like if you are planning to take photos at a Christmas party in someones house. If you know your subject will be far away, for example when shooting at a concert, then go for the 45mm. The caveat here is that if you don't work regularly with a longer focal length, you may find it challenging to compose everyday shots with the 45mm. 

Compression and Depth of Field

Theres a lot of chain on boats!
The difference in these two lenses' focal length also has an impact on the images "compression" or how far/close background objects appear to the subject. My methodology for showing the differences included shooting a photo at the 45mm's closest focus distance, switching lenses, and then trying to replicate the shot with the 25mm by moving my camera closer to the subject. Again, I am on a boat which is constantly moving and vibrating so I do not bring a tripod with me offshore. The "Doctor Who" example was shot with my camera on a table and the "Yellow Sign" example was shot handheld. Minor differences in my camera's positioning are notable but I tried my best to showcase the background renderings between each lens. 
  • Doctor Who
45mm, f/1.8, 1/30 sec, iso 200
25mm, f/1.8, 1/45 sec, iso 200
  • Yellow Sign
45mm, f/1.8, 1/180 sec, iso 200
25mm, f/1.8, 1/180 sec, iso 200
As you can see, in both examples, the background appears closer to the subject when using the 45mm. This is beneficial if you are trying to isolate your subject from a distracting environment and need diminish its contribution to the photo. However, if you are looking to shoot portraits where the background is needed to give context to your subject, the 25mm may be better suited. Here you can achieve a different type of isolation where the background appears far away from your subject. One other interesting thing to note is that in the first photo of Doctor Who, you can see the difference between the depth of field between the two lenses if you look at the table near the base of his feet. Not surprisingly, the 45mm's DOF is a tiny bit shallower at its closest focus distance. The photo below represents Doctor Who shot at the 25mm lens' closest focus distance and here you can see that the DOF narrows. In all practicality, the difference here is probably negligible as both lenses are highly capable of facilitating subject isolation.



Sharpness and Distortion


I do not know what to write about in this section besides stating that both lenses are very sharp, even wide open and to reference you to SLRgear who have conducted professional tests for both these lenses (45mm here and 25mm here). I found a figure on the side of the Viking I and decided to publish my own sharpness test finding here, but again, these were shot handheld on a boat and likely do not represent optimal conditions. RAW versions of the examples below were imported into Lightroom 4 and immediately exported as 100% quality 2000x2000 pixel JPEGS. After original files were exported they were cropped to 595x595 pixels and exported again without resizing to represent 100% crops.
  • 45mm at closest focus distance

100% crop
  • 25mm at same distance as 45mm closest focus distance (ie. I did not move between this example and the one before it)

100% crop
  • 25mm at distance to replicate 45mm closest focus distance (ie. I moved forward to focus on block "4")

100 % crop
  • 25mm closest focus distance

100% crop
From 100% crops it is very hard to tell if there is a difference in sharpness and really, any that might exist will not be noticeable in real world use. When you compare the first example showing the 45mm closest focus distance with the third example where I moved to try and replicate the 45mm closest focus distance's field of view you can see the 25mm exhibits some distortion. This is not really an issue when there is some distance between you and the subject (ie. in example two) and you can probably achieve results similar to the 45mm by taking the photo at a distance and then cropping in post (see this article for more details). 

Portraiture


To test out how the lenses compare when it comes to portraiture, I asked my co-worker and friend Greggo to subject himself as my model for a series of test shots. I wanted to show the differences in compression here and keep some of the background detail in these shots so my aperture was set to f/4 during the session. All the photos were processed in Lightroom 4 using the same preset and my own eye enhancement recipe. 

45mm
25mm at same distance as photo above
25mm closer to subject to try and mimic 45mm field of view

25mm at close focus distance
I really like all the photos I took of Greggo for this post and it is really hard for me to state whether I prefer the 25mm or 45mm lens for portraiture. What I can say is that I liked the abiliy to get really close to Greggo using the 25mm to capture the amazing details in his eyes. When comparing the first and third example you can see that the 45mm exhibits less distortion, but really, if I had only taken photos with the 25mm, I would not have seen the photo and thought it to be distorted. Below is an example of a photo taken at distance using the 25mm and cropped to give a similar field of view to the first 45mm example. I will let you decide on which lens looks better for portraiture, I think that they are both stellar performers on this front. 



Macro


I have written this section for those who like me may be interested in using either of these lenses as a macro alternative by using them with extension tubes. I wrote about using the Meike extension tubes with the 15mm body cap lens and used the 45mm portrait lens as a comparison here. This is a bit of an expansion on this as I was curious about the differences between how the 25mm and 45mm lenses render photos when coupled to the 10mm, 16mm, and 26mm (both) tubes I own. Below is an example of what magnifications are possible for the lenses without the extension tubes. They also give an idea of how I set up this test.
  
45mm at closest focus distance
25mm at closest focus distance of 45mm (ie I did not move the camera between this shot and the one before it)
25mm closest focus distance
The 25mm has a close focus distance of about 9 inches (24 cm), so its maximum magnification (0.12x) without the extension tubes is greater than that of the 45mm whose close focus distance is a whopping 1.64 feet (apx 0.5 m). The photos below show how the magnification of the 25mm compares to the 45mm when attached to the different extension tube sizes.
  • 10mm Extension Tube
45mm
25mm
  • 16mm Extension Tube
45mm
25mm
  • 10mm + 16mm Extension Tube
45mm
For all of the shots above, my camera's kit flash was set to "fill" and I let my camera meter the photos. I did not post 100% crops because the length of this article is already bordering ridiculous and they were all basically super sharp. The main thing to note here is that the 25mm lens has an overall greater magnification, but it can only be used with the 10mm extension tube. When used with the 16mm extension tube, the lens' barrel needs to be quite close to the subject and the kit flash becomes shaded. Of course, if you use off camera lighting for your macro shots this will be less of a concern. Even so, you will need to get really close to whatever you want to take a photo of using the 25mm. Overall I think the 45mm is a better macro alternative because it's greater close focus distance translates into having more working distance when used as a macro. If you are looking for the most magnification possible, I would consider coupling the extension tubes to the ultra inexpensive 15mm body cap lens.

15mm BCL and 10mm extension tube
15mm body cap lens and 16mm extension tube
Summary Table:



Conclusion


The intent of this comparison was to give the micro four thirds community some examples of what the 45mm and 25mm have to offer. Both of them are awesome in my opinion and I cannot say I prefer one over the other. I think this is because when I started my venture into photography last year, I started learning on a 50mm f/1.8 (100mm equivalent) and I will always consider this longer focal length special. That being said, since I got the 25mm, I havent been able to put it down! If you are on the fence about getting one of these two lenses, ask yourself whether you want/need a versatile everyday lens or a specialized portrait lens that you are wiling to practice with in order to use as a walk around lens. If you fall into the "former" category then go for the 25mm, its sharp, fast and great for general photography. If you want to make sure there is not an drop of perspective distortion in your portraits then go for the 45mm, plus it can double as a macro. I was going to write about differences in bokeh, but really if you look at all the sample images above you can see that they both produce pleasing out of focus areas. I do not know if I will get rid of one over the other because I can see myself using both in different situations. Hopefully I have provided some helpful information here, Thanks for dropping by!

Sam D.




Additional 45mm Sample Images

Check out my original low light performance review here.





  • Non offshore images

I couldn't stop taking photos of cats after I got this lens






  • Macro using extension tubes








Additional 25mm Sample Images