Olympus Pen EP1 underwater settings

[sentlon]

I remember that you have to close the diaphragm a bit. I do not have soft corners when I use it at F8 or even f5.6. I never go below. I think it has to do with the way the virtual image focuses in front of the dome. At F4 it seems to be non optimal or the design had to compromise a bit (but this is only a conjecture and I certainly cannot prove it).
Sometimes I also do a bit of post SW correction of the distortion and it helps outline the details quite a bit. The lens and the dome are great. The dome you can use it with the 45mm macro, 14-42mm kit lens and and the 9-18mm. I also read the 12mm works with it (but i do not have it so I would not swear for it).

close the

diaphragm? i don get what u mean, is it in the camera setting?​

 

[smoore]

close the

diaphragm? i don get what u mean, is it in the camera setting?​

That means using a higher f stop. The diaphragm controls the amount of light which reaches the sensor. The higher the number the less light that reaches the sensor. This is accomplished through a metal diaphgragm that at higher f stops (aperatures) closes down the metal diaphragm behind the lens which allows less light to reach the sensor. It is as if at a lower f stop that you are shooting through a hole with wide diameter and at a higher f stop the diameter of the hole in the adjustable diaphragm is smaller. Up to a point closing the aperature increases the depth of field which allows more of the picture to be in focus. It is not unusual for very wide lenses to have some fuzziness at the edges. Closing the lens down can minimimize this. Some of the earlier posts indicate that some photographers have found it necessary to zoom to higher focal length (something higher than the widest angle of 9 mm.) to avoid this fuzziness or edge distortion. I haven't worked with this lens enough to have a feel for this issue.

 

[PHIL RUDIN]

Until the poster of the photos also posts the settings used to take the photos (camera mode, ISO, shutter speed, F/stop, IS on/off, focus point etc.) making a judgement about how to improve the images will be at best a guess. If the camera was set to auto it may have picked F/4 at 1/15th sec at ISO 1600 and you would not expect to see sharp focus in both the foreground and background. If the image was taken using auto focus and the point of focus was 10 meters from the foreground you would expect the forground to be out of focus. Not enough information.

It is however clear that the lens at 9mm with the Zen dome works quite well stopped down one or two F/stops.

Phil Rudin

 

[under water]

what actually drive this issue of it ?
is the lens or the dome cause it?
after spending many budget on it, cant believe it cause so much degrade of pics.

I had the exact same issue when I used the 9-18mm lens with the Zen dome and found that I needed to close the aperture down to at least F8 to minimize (not eliminate) the fuzzy edges. The 9-18mm lens does not have this issue above water. I think it is the dome.

 

[sentlon]

I had the exact same issue when I used the 9-18mm lens with the Zen dome and found that I needed to close the aperture down to at least F8 to minimize (not eliminate) the fuzzy edges. The 9-18mm lens does not have this issue above water. I think it is the dome.

indeed, i have test it above water. it never have this problem. i really suspect that issues from Dome.

 

[sentlon]

Until the poster of the photos also posts the settings used to take the photos (camera mode, ISO, shutter speed, F/stop, IS on/off, focus point etc.) making a judgement about how to improve the images will be at best a guess. If the camera was set to auto it may have picked F/4 at 1/15th sec at ISO 1600 and you would not expect to see sharp focus in both the foreground and background. If the image was taken using auto focus and the point of focus was 10 meters from the foreground you would expect the forground to be out of focus. Not enough information.

It is however clear that the lens at 9mm with the Zen dome works quite well stopped down one or two F/stops.


Phil Rudin

It is however clear that the lens at 9mm with the Zen dome works quite well stopped down one or two F/stops.

the pics is taking at 1/180th sec F/4 focus is center. iso 400.
in this case, what you suspect the issue cause by?

however, i found out those taking more then f/5.6 still struggle for the softness of corner.

 

[sentlon]

I had the exact same issue when I used the 9-18mm lens with the Zen dome and found that I needed to close the aperture down to at least F8 to minimize (not eliminate) the fuzzy edges. The 9-18mm lens does not have this issue above water. I think it is the dome.

it seem we are in the same setup and having the same issues.
should we bring out this to Zen ?
i still need more feedback from the same setup.
i wondering 7-14 pana lens have the same issues when pair with the Zen WA 100?

 

[PHIL RUDIN]

Online Depth of Field Calculator


The issue is more with the settings you are using than with the Zen dome port. Look at the attached link and calculate your DOF at the settings you were using. No way the foreground would have been in focus using those settings. Had you closed the lens down to say F/8 and used a slower shutter speed of around 1/60th you would have had much great depth of field and still had light to expose the image without camera shake. At 9mm you can shoot at 1/15th of a second and still not blur the image, with IS even slower. Next when you look at the DOF charts you will see that if you lock focus on the foreground ( say one foot and not in the center of the frame which looks to be 4 or 5 Ft. away) and then re-frame you will have much more of the foreground in focus while still having a sharp image 5 or 6 feet away.

I would suggest that you get hold of a good book on the subject like "The Underwater Photographer" by Martin Edge (4th edition) to help understand how you can best use your equipment.

Regards,

Phil Rudin