Oly 60mm + diopter question

[Furnari]

I stuck a crowbar in my wallet and picked up the 60mm for my E-PL2 since it's on sale again. As I've already got the Olympus wet lens and clip on adapter, is there any benefit to shooting it with the 60mm, or will the depth of field be too narrow? I'll typically be dealing with low viz conditions (6-10 expected for this weekend), but I've got dual strobes and a focus light so I can always stop down the aperture.

On a tangent- how does the Oly diopter compare to other macro wet lenses? They use a different measuring stick, so I guess it equates to a +5. Haven't been able to find too much out there on it...

 

[jlyle]

I have used a SubSee +10 with the 60mm macro lens. It's always nice to have the ability to take pictures of even smaller critters when they present themselves. Yes, DOF is credit card thin but why crop an image when you can fill the frame?

Don't expect big magnification with any of the diopters, just a tad more. The minimum working distance is decreased with a diopter.

 

[Interceptor121]

The olympus diopter is pretty weak compared to other lenses and is not really worth it with a 60mm lens, it is more for a zoom lens shooting at tele end (14-42 kit lens)

With a 60mm macro you will have a focus distance around 25cm so you need at least a +6 or +10 diopter to improve matters that will give you 1.7:1 or 2.4:1

 

[jlyle]

Interceptor121, I believe the minimum focus distance with the 60 mm macro is 19 cm. No?

 

[Interceptor121]

On land. In water with flat port will be more

 

[Foxtrot16]

On land. In water with flat port will be more

I find that on my EM-5 behind the Nauticam M65 or M77 (for the 12 - 50mm lens) ports its still 19 cm. When I add the Subsea +10 to the front the minimum distance is about 10cm and the depth of field is greatly reduced as is the focus - i.e. you only have to move a couple of mm for the focus to go so you need a very steady hand and no current etc to get really good sharp images.

Also remember when using the dioptre that the camera is taking a virtual image created by the dioptre therefore you need to get the focus right with the dioptre first before you focus the camera - i.e. you need to ensure that you can see a clear image on you LCD screen or in the view finder first by moving the dioptre back and forwards and once you have done this then you can focus the camera.

Karl

 

[Interceptor121]

I would be surprised as the flat port will have an effect on focus distance. This will be different based on the amount of space between the top of the lens and the glass port. Generally as you have magnification you will step back to achieve the same performance on land at increased distance. Typically you do times 1.33x for practical use. Consider that the distance from the top of the port is not the focus distance so if you measure 19 from the port is actually more

 

[John Gulliver]

On land. In water with flat port will be more

Is this really true? According to what I've read, it isn't.

 

[Interceptor121]

What have you read? I would be interested understanding how. From my tests not with this lens there is a difference

Some physics focal length in water is 1.25x focal length on land. 60mm becomes 75mm
Focal length and minimum focus distance are related hence the values in water and air can't be the same and the lens minimum focus distance underwater will change with a flat port
For a dome this doesn't apply

 

[jd950]

Furnari: Check this page for some information that may help with your questions:

Underwater Visions - Nauticam UK - Underwater Housings

The link is to their homepage but there are sub-pages with a bunch of information about diopters and such. (I have no connection to these folks, but thought their page might be informative)