Dermlite DL3 Dermatoscope, review in progress.

I'm going to write this up in English, as there are few available online reviews of dermatoscopes.

Introduction:
I have been using a Welch Allyn Episcope for some time now, but wanted to be able to take photos of lesions, which, in some instances, would enable me to send images to a specialist instead of referring the patient or removing a possibly benign lesion.
The choice came down to the either the Heine Delta 20 or one of Dermlite's options.
The DL3 appealed to me because it could do both cross-polarized and non-polarized dermoscopy.



I already owned a mirrorless interchangeable-lens camera (Olympus E-P1), but it had an older version of the kit-lens that had a rotating, and extending filter-adapter, rendering it useless for this because it tries to turn the whole dermatoscope when you try to focus.
I therefore bought a used, and upgraded lens.



Note the "MSC" designation and 37mm filter-adapter.
You will need to get a 37-28mm step-down ring, pictured below (got it on Ebay.co.uk for 50kr/$8)



The dermatoscope attaches easily like so:

I set a fixed focal length of 20mm, iso to 200, shutter speed to 200, and aperture to F/9.
This gives me good and sharp images using auto-focus:

The DL3 will let you switch between cross-polarized light, so that you can use it without immersion fluid and/or compression of the skin (lets you view vessels a lot better), and regular non polarized light, requiring immersion fluid. It is substantially better than my Welch Allyn in both modes, but I have not compared it to the Heine (others have though, and write that they are equally good for non polarized dermoscopy, and the Heine won't do cross-polarized).

 

The DL3 was rather expensive at 888 euro, I already owned the Welch Allyn, but I think the DL3 is substantially better, and being able to take pictures has advantages.

First of all my practice will get reimbursed for some of the expenses when we send the pictures to specialists, secondly we will be able monitor appropriate lesions by storing images, and thirdly it's a great tool for sharpening your skills, as you can look at lesions with your practice partners at the end of the day.

The ability to use cross-polarized light should not be underestimated. With it you are able to look at a lot more lesions in secession, because you don't have to reapply oil or alcohol the whole time, suddenly making it feasible to do a full body examination in a relatively short time. 

I still prefer to have the ability to use non-polarized light because some features are more visible using this mode (other features are more visible using cross-polarized).

Some notes on the choice of camera and lens:

I have chosen the E-P1 because you can get them dirt cheap on Ebay, even brand new (its 4 generations old). There is no reason to get a newer version, but the E-P2 and E-P3 can also be had pretty cheap and I think they come with the required lens standard. All the E-PX'cameras are extremely well built and easy to control. 

You can also use a lot of compact cameras, but they will require a special adapter to accommodate the 28mm filter adapter on the dermatoscope. An SLR would also be great, but I have no suitable lens for my Canon 5D.

Be aware that most lenses for interchangeable lens cameras have either a rotating filter thread or a front that moves when you focus. Be absolutely sure that you get a lens that has "internal focus".

You get a full field of view using a focal length of approximately 35-40mm on a 35mm/full frame camera. This means that on Micro Four Thirds (such as the E-P1) you will use a focal length around 18-20mm. A standard 3x zoom lens will be fine.

Using a compact such as a Canon G14 will probably give you very good pictures with good depth of field, without having to use an aperture as small as I do, but the light form the DL3 is so bright that you can just use f/9 og even smaller if you increase the ISO as you can on the E-P1.

The E-PM1 is very cheap, has the lens you need, and is easy to use for a beginner (more geared towards point and shoot than the E-P1). I got one for 1500kr ($250) brand new on Ebay. The E-PM3 can be had for around 2000kr with lens and is a great buy.

The reasons why I use this camera, are that it has good high iso performance, enabling you to take pictures without using flash, and the Olympus cameras also have good auto white balance, so the florescent light in the clinic is no problem when taking pictures of skin lesions. It turns out it's also very good for dermatoscopic photos.

Please check this page if you are interested in learning more about dermoscopy:

http://almenmedicin.blogspot.dk/p/blog-page.html

I hope you enjoyed the review. Let me know if have any questions.

Christian Tørring, August 2013



Added jan 2014: