Compare to other fresh fruit, raspberries are intensely flavorful and very tart, so to make ice cream you need less fruit and more sugar.
Toss the raspberries, 3/4 cup sugar, and the lemon juice together in a bowl. Cover and refrigerate for 2 hours, stirring every 30 minutes. Whisk the eggs in a mixing bowl until light and fluffy, 1-2 minutes. Whisk in thr remaining 3/4 cup sugar, a little at a time, then continue whisking until completely blended, about 1 minute more. Pour in the heavy cream and milk and whisk to blend. Drain the juice from the raspberries into the cream mixture and blend. Mash the raspberries until pureed and stir them into the cream mixture. Transfer the mixture to an ice cream maker and freeze following the manufacturer's instructions.
Makes 1 generous quart.
NOTE: If you prefer a chunkier raspberry ice cream, return the raspberries to the refrigerator after pouring off the juice. After the ice cream stiffens, about 2 minutes before it is done, add the whole raspberries.