Lens equivalent in mm

[cowasaki]

If I have a MAK 180 scope and attach my camera to the eye piece what would the "equivalent" lens mm be?

This is just out of interest

[John]

Assuming that we are talking about the Skywatcher Skymax 180 Maksutov-Cassegrain scope and that the camera body alone is attached, the scope is the equivalent of a 2,700mm focal length lens I think.

[cowasaki]

Assuming that we are talking about the Skywatcher Skymax 180 Maksutov-Cassegrain scope and that the camera body alone is attached, the scope is the equivalent of a 2,700mm focal length lens I think.

Thanks, I was just interested. The best I've managed so far is my 200mm with a 1.4TC giving me 280mm whilst shooting the moon. I normally photograph much smaller and closer items

[John]

Thanks, I was just interested. The best I've managed so far is my 200mm with a 1.4TC giving me 280mm whilst shooting the moon. I normally photograph much smaller and closer items

I still get confused with all that - I was bought up on 35mm SLR's and can't get used to the digital scale of things.

I used to use a set of extension tubes with a 50mm lens for close up stuff - they don't seem to be needed these days

[cowasaki]

I still get confused with all that - I was bought up on 35mm SLR's and can't get used to the digital scale of things.

I used to use a set of extension tubes with a 50mm lens for close up stuff - they don't seem to be needed these days

No that was a 200mm lens and 1.4x tele convertor attached to my full frame camera i.e. the same as it would be on film. If I'd attached the two to my crop sensor it would have been another x1.4 making it just under 400mm.

[Adrian]

The focal length of a scope should equate to a lens (or near enough for the skymax) that length but the FOV of a camera, especially a full frame one, will make the apparent magnification lower than with most eyepieces.

With the narrow aperture at the rear of the skymax you may also get some serious vignetting if you use full-frame.

I used to use a set of extension tubes with a 50mm lens for close up stuff - they don't seem to be needed these days

I have set for my DSLR - still the best for getting really close I find they work nicely with a nifty fifty: Forget-me-not and Dandelion.

[cowasaki]

I find a proper macro lens is better though

Nikon AFS 105mm f2.8G on D700

[Adrian]

OOoooH - That'll take nice astrophotos too. Unfortunately my lens money is still at £0, coming after mount fund and eyepiece savings

[cowasaki]

Is there an equation to work this out?

[jgs001]

I just treat the scopes as telephoto lenses Darren... so 600mm scope is a 600mm telephoto lens (only simpler and much cheaper) on a full frame camera.

[cowasaki]

I just treat the scopes as telephoto lenses Darren... so 600mm scope is a 600mm telephoto lens (only simpler and much cheaper) on a full frame camera.

Cheers! It was just out of interest.

Oh and my scope is here!

MAK180, NEQ6 SynScan, decent eye pieces & the original ones plus some other bits and pieces.

[jgs001]

Very nice

[cowasaki]

I'm looking forward to having a play. I've just ordered an ST80, making every photon count and the bits for attaching the camera Hoping I'll be well enough in a week or so to at least put it together.

[jgs001]

That's no good Darren... lots of new toys and sick... Hope you feel better soon

[cowasaki]

That's no good Darren... lots of new toys and sick... Hope you feel better soon

Thanks, at least I know it is there and it's sorted etc. The whole lot looks like new, he said he's only used it twice and it really looks like it. Only thing I'm short of is a battery pack but I'm going to sort that. Even though I'll have the guide scope and camera bits, thats mainly so that I have them and I don't spend the money!

[jgs001]

what you gonna use as a guidecam ?

[cowasaki]

what you gonna use as a guidecam ?

The ST80 that I bought today.

I'm going to buy a self contained guide cam at the end of next month to use for now but I am already designing a complete stand alone guide camera/controller/power/camera controller system (which I hope to build into a peli case) - My water droplet computer is 50% of the design having the menu system, real time clock and camera control stuff already in the circuit and programming.

[jgs001]

ah gotcha... That sounds interesting... Be interested to know more of your droplet computer (but probably best not in this thread... we've meandered off topic enough I reckon )

[cowasaki]

ah gotcha... That sounds interesting... Be interested to know more of your droplet computer (but probably best not in this thread... we've meandered off topic enough I reckon )

Yes I think we have. I posted a picture in another thread.

[Capricorn]

Never sure of this equivalent argurement.

The image size is the same irrespective of the sensor, 35mm film or "standard" digital camera. The digital camera just samples a smaller proportion of the image.

This smaller proportion is the same angle as if the person had a longer lens but as said the image on the sensor is not that of the mythical "longer" lens, it is that of whatever lens focal length is.

It seems to be a way in which manufactures have managed to convince people they are getting something better then they actually are.

If you put a 200mm lens on a standard digital camera the image seen is a smaller bit of the image created by the 200mm lens then if you had a 35mm sensor at the same place. There is no additional magnification to make the image as if it were a 300mm lens, just you see only a smaller bit. You lose something, not gain something.