DSLR wont focus with lens removed

[juleznz]

KiaOra everyone im sure you would have covered this topic before but here goes

So i have a celestron astromaster 130 EQ MD I purchased a barlow ,T2 adpapter ring etc for my Nikon D3300

I attach it camera gives me the you have no lens attached msg and so then i tried live view nothing

Cant find anything on world wide web about this that is helpful anyway

Please help any tips ideas methods gratefully considered

Thanks

Julie-Ann

[Thalestris24]

Hi Julie-Ann

I don't know your camera but you need to have it set to manual mode.

Hope that helps

Louise

[juleznz]

Hi Louise yep had it set to manual il keep trying thanks for your reply tho:)

[ronin]

Following on from Louise, there is/may be 2 manual modes:- one for the lens, usually a switch on the side of the camera where the lens attaches and there is the mode of operation dial on the top (left usually) of the camera. You may need both set to manual.

On mine, not a Nikon, there is also a switch somewhere for the live view itself.

When you say nothing on live view do you mean it is dead, doing nothing, or is it on but the image of the sky is featureless and so uniform across it all? Only ask as when you attach the camera the focus will be way off and there will be no focussed image on the sensor and so no "image" fed back to the live view to be seen - it will look "blank". If this then easiest I can think of is attach camera etc and then shine a torch across the front to the scope while you look at the live view. It should brighten if it is operatiing.

The other option could be the worst, no recognised lens = no live view.

 

[iapa]

Hi,

As Louis noted, you have not said which make/model of DSLR you are using.

I have Nikon D90, Canon 700D and 70D. I also have a Celestron 130 reflector (f5, 650mm). (actually, I have two, the EQ and the SLT). I also used an Olympus eOS 450 at one time.

I can't remember that I did anything in particular with the DSLRs to use on the telescopes - I just remove the sense, attach the T2, nosepiece and Barlow, and it's fine.

You do not say if you have a barlow. With the M2 adapter and nose piece, you cannot actually achieve focus with these unless you purchase a Barlow lens.

I was just wondering if the focus is so far off you are just getting a smooth image?

The reason for this is that the focus point for the this telescope is inside the draw tube, as the eye piece lenses project in to the draw tube. The focus needs to be at the surface of the camera sensor, which is about 1" or so further out.

[MarkyD]

Canon has a setting to ignore a missing lense else it throws up an error.  Does the Nikon not have the same?  You should be able to still use the body just not auto focus or VR obviously

--

Mark

[happy-kat]

Camera must be in manual mode, ignore the no lens message. You set the iso and exposure length. You use the telescope focuser to focus. You will need to either use the timer or a remote shutter release or you'll get blurry photos.

Try it all out during the day on a very distant chimney, tree, aerial (not the sun). Get a feel for how it all works.

[Dr_Ju_ju]

Hi Julie-Ann,

One thing to confirm before you have even turned on your camera, is to check that you can achieve focus... 

This can be done during the day, by attaching the camera to your OTA with T mount\barlow etc. and try looking through the viewfinder at a remote object, by using the focuser on the OTA.

Depending at which end of the focus racking you reach focus (if at all), you may need additional T extension rings or a way of shortening the distance....

 

[Jannis]

Just to confirm - you say "nothing", but does that mean a completely black screen, or just out of focus? Try to shine a flashlight into the scope while on live-view to see if it does indeed respond. If it responds, increase your exposure and/or ISO to get a more dark gray image before going any further.

Most likely it's just so far out of focus that you don't see anything. Telescopes, in difference to lenses, are very sensitive to focus points, and can also go far out of focus in comparison.
It might be that you also need an extension ring between the camera and scope to reach focus (i need this, and it's not uncommon).

Also, do check all this during the daytime. A lot easier to focus on a forest far away then a star or street lamp you have no idea if you're even pointing at during the night.

[juleznz]

Thanks everyone for your input ive sorted camera and can see in live view now and have a camera adapter also barlow x 2..im looking at crescent moon tonight and to be honest its no better than a 300mm lens on camera ..i was expecting clearer detail with a 650mm focal length scope?...

[Jannis]

You do indeed get a higher resolution with the 650mm compared to the 300mm lens. However, there are some factors you need to keep in mind. 

One of them is seeing. If this is bad, you'll get a blurry picture no matter what, but the image will look sharper the shorter your focal length is. The lower on the sky the moon is, the more you're affected by seeing condition. A quick way to check is to see if the stars around the moon area is flickering a lot. If they are, seeing is bad. This is common right after sunset as the earth is cooling down. 

It's the same as when you open a window in the winter time and you look outside trough it and you see that it get's all blurry from the heat escaping and mixing with the cold air.

Also, this is the reason why we usually don't take pictures of the moon, but either record a video or take many many pictures and throws away 90-95% of them and use only the sharpest ones and combine the sharpest parts from these to a final image.

Here's an example of "a pic" i've taken handheld with the 550D and a 200mm zoom lens. As you can see, stacking them creates a much more clear picture. 
This is a very low res image though, taken with only 640*480 resolution (0,3Mpixels).

Single frame:

Stacked frames:

Stacked and processed:


And a video i made describing how i did it: 

Basically, a high focal length doesn't automatically mean a crisp and clear picture, it only gives you the possibility for a higher detailed one.  

[juleznz]

wow thank you so much i feel inspired again i had such high hopes from the scope but my attempts have been disappointing..its so true about dont take any notice of the pics on the box lolz my post processing is still hit and miss still tons to learn or figure out

[Jannis]

I think you added that picture right after i replied? There appears to have been a significant loss in quality in the resize or saving process, so it's hard to judge the picture in full. 

It appears the focus is good, but the brighter parts are strongly overexposed and can't be saved. ISO/exposure time is set too high.  
Hopefully you have a tracking mount, in which case i recommend you set your ISO to 100-400, and lower the exposure down so that the brightest parts are exposed high, but not burned out. The darkest parts may then look too dark on the camera, but you can usually drag out the details later when processing. Remember to shoot in RAW.

[juleznz]

Thanks for your advice in my last shot i hadnt had telescope outside very long it was windy and warm ..last night i tried movie broke frames down in PiPP like you suggested tried stacking in avistack but that was total mess dunno what i did wrong there but ended up light process of a single frame in LR this is the improved result

[Jannis]

Wow thats a huge improvement!

Very few use avistack as its slow and hard to use. I find IT better, but requires a lot of time and work.

Try registax instead, Very popular, free, Quick and easy

[juleznz]

Thank you heaps for your advice im chuffed with improved outcome...hmm stacking programs dont like me haha tried registax and this is what i got haha

[Filroden]

7 hours ago, juleznz said:

Thank you heaps for your advice im chuffed with improved outcome...hmm stacking programs dont like me haha tried registax and this is what i got haha

I don't know what you've done but I love it! It looks like you've spooned the moon.

[carastro]

Whenever I have shot the Moon with a DSLR I have taken quick shots of Jpegs (not using the AVI mode) and stacked about 10 together in Registax.  Registax doesn't like too many large files imported at the same time, so I stacked in batches and then stacked the resulting batches.  

 

Interesting stack you got from Registax.  

I used AV and 100iso to get this shot:

 

 

[Jannis]

I think the problem is your settings for referance points. They dont match and line up, causing just a messy result. If you can upload 2 untouched frames at full res im sure we can guide you to a registax setting that will work properly for your frames - or at least let you know whats wrong with the frames and what needs to bechanged.