I am posting my results for a clever new Osram category of bulbs, called Ministar.
There is a thread about the 35W version here, but I ordered and tested the 50W version.
This bulb has a high quality silver coating on the bottom, acting like a reflector, and improving efficiency similar to the IRC bulb. Because this is a more directional bulb, Osram rates it in candela.
As I have said elsewhere,
there are very strict definitions of lumens and candela, that are rarely understood. Candela underscores the measurement output in a directional cone of light (called a steradian) which applies more accurately with this type of built in reflector coating.
Luckily, we can do an approximate conversion by
looking at Osram's site for the 50W Ministar bulb here, which I just finished testing. I will be posting it in my destructive original post shortly.
We see that this bulb puts out 1400 candela with radiation angle of 30° (also has life of 2,000hrs and color temp of 3,000 K).
Going back to the WIKI page, there is a conversion table at the bottom if you know the beam angle, which in this case 30° uses 4.67.
So we divide 1400 candela by 4.67 to get
approximately 300 lumens. However, this is a totally unique bulb design, because of directional output, but I did my same perdicular lux testing method to be consistent.The obvious question is how does it compare to the
IRC 50W 64440 bulb listed here. That bulb lists 1250 lumens & 4,000hr life (same 3,000K temp), and at first blush it appears the IRC blows it away.
I will have to additionally test both bulbs in the same reflector setup to see how they compare visually and practically. The Ministar reflector design makes an unfair "apples to oranges" comparison. You can use my data to see the low amp efficiency and flash point voltage.
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